OpenCloudOS-Kernel/drivers/block/ublk_drv.c

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ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Userspace block device - block device which IO is handled from userspace
*
* Take full use of io_uring passthrough command for communicating with
* ublk userspace daemon(ublksrvd) for handling basic IO request.
*
* Copyright 2022 Ming Lei <ming.lei@redhat.com>
*
* (part of code stolen from loop.c)
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/major.h>
#include <linux/wait.h>
#include <linux/blkdev.h>
#include <linux/init.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/compat.h>
#include <linux/mutex.h>
#include <linux/writeback.h>
#include <linux/completion.h>
#include <linux/highmem.h>
#include <linux/sysfs.h>
#include <linux/miscdevice.h>
#include <linux/falloc.h>
#include <linux/uio.h>
#include <linux/ioprio.h>
#include <linux/sched/mm.h>
#include <linux/uaccess.h>
#include <linux/cdev.h>
#include <linux/io_uring.h>
#include <linux/blk-mq.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <asm/page.h>
#include <linux/task_work.h>
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
#include <uapi/linux/ublk_cmd.h>
#define UBLK_MINORS (1U << MINORBITS)
/* All UBLK_F_* have to be included into UBLK_F_ALL */
#define UBLK_F_ALL (UBLK_F_SUPPORT_ZERO_COPY \
| UBLK_F_URING_CMD_COMP_IN_TASK \
| UBLK_F_NEED_GET_DATA)
/* All UBLK_PARAM_TYPE_* should be included here */
#define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD)
struct ublk_rq_data {
struct callback_head work;
};
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
struct ublk_uring_cmd_pdu {
struct request *req;
};
/*
* io command is active: sqe cmd is received, and its cqe isn't done
*
* If the flag is set, the io command is owned by ublk driver, and waited
* for incoming blk-mq request from the ublk block device.
*
* If the flag is cleared, the io command will be completed, and owned by
* ublk server.
*/
#define UBLK_IO_FLAG_ACTIVE 0x01
/*
* IO command is completed via cqe, and it is being handled by ublksrv, and
* not committed yet
*
* Basically exclusively with UBLK_IO_FLAG_ACTIVE, so can be served for
* cross verification
*/
#define UBLK_IO_FLAG_OWNED_BY_SRV 0x02
/*
* IO command is aborted, so this flag is set in case of
* !UBLK_IO_FLAG_ACTIVE.
*
* After this flag is observed, any pending or new incoming request
* associated with this io command will be failed immediately
*/
#define UBLK_IO_FLAG_ABORTED 0x04
/*
* UBLK_IO_FLAG_NEED_GET_DATA is set because IO command requires
* get data buffer address from ublksrv.
*
* Then, bio data could be copied into this data buffer for a WRITE request
* after the IO command is issued again and UBLK_IO_FLAG_NEED_GET_DATA is unset.
*/
#define UBLK_IO_FLAG_NEED_GET_DATA 0x08
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
struct ublk_io {
/* userspace buffer address from io cmd */
__u64 addr;
unsigned int flags;
int res;
struct io_uring_cmd *cmd;
};
struct ublk_queue {
int q_id;
int q_depth;
unsigned long flags;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
struct task_struct *ubq_daemon;
char *io_cmd_buf;
unsigned long io_addr; /* mapped vm address */
unsigned int max_io_sz;
bool abort_work_pending;
unsigned short nr_io_ready; /* how many ios setup */
struct ublk_device *dev;
struct ublk_io ios[0];
};
#define UBLK_DAEMON_MONITOR_PERIOD (5 * HZ)
struct ublk_device {
struct gendisk *ub_disk;
char *__queues;
unsigned short queue_size;
struct ublksrv_ctrl_dev_info dev_info;
struct blk_mq_tag_set tag_set;
struct cdev cdev;
struct device cdev_dev;
#define UB_STATE_OPEN 0
#define UB_STATE_USED 1
unsigned long state;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
int ub_number;
struct mutex mutex;
ublk_drv: fix lockdep warning ub->mutex is used to protecting reading and writing ub->mm, then the following lockdep warning is triggered. Fix it by using one dedicated spin lock for protecting ub->mm. [1] lockdep warning [ 25.046186] ====================================================== [ 25.048886] WARNING: possible circular locking dependency detected [ 25.051610] 5.19.0-rc4_for-v5.20+ #149 Not tainted [ 25.053665] ------------------------------------------------------ [ 25.056334] ublk/989 is trying to acquire lock: [ 25.058296] ffff975d0329a918 (&disk->open_mutex){+.+.}-{3:3}, at: bd_register_pending_holders+0x2a/0x110 [ 25.063678] [ 25.063678] but task is already holding lock: [ 25.066246] ffff975d1df59708 (&ub->mutex){+.+.}-{3:3}, at: ublk_ctrl_uring_cmd+0x2df/0x730 [ 25.069423] [ 25.069423] which lock already depends on the new lock. [ 25.069423] [ 25.072603] [ 25.072603] the existing dependency chain (in reverse order) is: [ 25.074908] [ 25.074908] -> #3 (&ub->mutex){+.+.}-{3:3}: [ 25.076386] __mutex_lock+0x93/0x870 [ 25.077470] ublk_ch_mmap+0x3a/0x140 [ 25.078494] mmap_region+0x375/0x5a0 [ 25.079386] do_mmap+0x33a/0x530 [ 25.080168] vm_mmap_pgoff+0xb9/0x150 [ 25.080979] ksys_mmap_pgoff+0x184/0x1f0 [ 25.081838] do_syscall_64+0x37/0x80 [ 25.082653] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.083730] [ 25.083730] -> #2 (&mm->mmap_lock#2){++++}-{3:3}: [ 25.084707] __might_fault+0x55/0x80 [ 25.085344] _copy_from_user+0x1e/0xa0 [ 25.086020] get_sg_io_hdr+0x26/0xb0 [ 25.086651] scsi_ioctl+0x42f/0x960 [ 25.087267] sr_block_ioctl+0xe8/0x100 [ 25.087734] blkdev_ioctl+0x134/0x2b0 [ 25.088196] __x64_sys_ioctl+0x8a/0xc0 [ 25.088677] do_syscall_64+0x37/0x80 [ 25.089044] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.089548] [ 25.089548] -> #1 (&cd->lock){+.+.}-{3:3}: [ 25.090072] __mutex_lock+0x93/0x870 [ 25.090452] sr_block_open+0x64/0xe0 [ 25.090837] blkdev_get_whole+0x26/0x90 [ 25.091445] blkdev_get_by_dev.part.0+0x1ce/0x2f0 [ 25.092203] blkdev_open+0x52/0x90 [ 25.092617] do_dentry_open+0x1ca/0x360 [ 25.093499] path_openat+0x78d/0xcb0 [ 25.094136] do_filp_open+0xa1/0x130 [ 25.094759] do_sys_openat2+0x76/0x130 [ 25.095454] __x64_sys_openat+0x5c/0x70 [ 25.096078] do_syscall_64+0x37/0x80 [ 25.096637] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.097304] [ 25.097304] -> #0 (&disk->open_mutex){+.+.}-{3:3}: [ 25.098229] __lock_acquire+0x12e2/0x1f90 [ 25.098789] lock_acquire+0xbf/0x2c0 [ 25.099256] __mutex_lock+0x93/0x870 [ 25.099706] bd_register_pending_holders+0x2a/0x110 [ 25.100246] device_add_disk+0x209/0x370 [ 25.100712] ublk_ctrl_uring_cmd+0x405/0x730 [ 25.101205] io_issue_sqe+0xfe/0x2ac0 [ 25.101665] io_submit_sqes+0x352/0x1820 [ 25.102131] __do_sys_io_uring_enter+0x848/0xdc0 [ 25.102646] do_syscall_64+0x37/0x80 [ 25.103087] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.103640] [ 25.103640] other info that might help us debug this: [ 25.103640] [ 25.104549] Chain exists of: [ 25.104549] &disk->open_mutex --> &mm->mmap_lock#2 --> &ub->mutex [ 25.104549] [ 25.105611] Possible unsafe locking scenario: [ 25.105611] [ 25.106258] CPU0 CPU1 [ 25.106677] ---- ---- [ 25.107100] lock(&ub->mutex); [ 25.107446] lock(&mm->mmap_lock#2); [ 25.108045] lock(&ub->mutex); [ 25.108802] lock(&disk->open_mutex); [ 25.109265] [ 25.109265] *** DEADLOCK *** [ 25.109265] [ 25.110117] 2 locks held by ublk/989: [ 25.110490] #0: ffff975d07bbf8a8 (&ctx->uring_lock){+.+.}-{3:3}, at: __do_sys_io_uring_enter+0x83e/0xdc0 [ 25.111249] #1: ffff975d1df59708 (&ub->mutex){+.+.}-{3:3}, at: ublk_ctrl_uring_cmd+0x2df/0x730 [ 25.111943] [ 25.111943] stack backtrace: [ 25.112557] CPU: 2 PID: 989 Comm: ublk Not tainted 5.19.0-rc4_for-v5.20+ #149 [ 25.113137] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-1.fc33 04/01/2014 [ 25.113792] Call Trace: [ 25.114130] <TASK> [ 25.114417] dump_stack_lvl+0x71/0xa0 [ 25.114771] check_noncircular+0xdf/0x100 [ 25.115137] ? register_lock_class+0x38/0x470 [ 25.115524] __lock_acquire+0x12e2/0x1f90 [ 25.115887] ? find_held_lock+0x2b/0x80 [ 25.116244] lock_acquire+0xbf/0x2c0 [ 25.116590] ? bd_register_pending_holders+0x2a/0x110 [ 25.117009] __mutex_lock+0x93/0x870 [ 25.117362] ? bd_register_pending_holders+0x2a/0x110 [ 25.117780] ? bd_register_pending_holders+0x2a/0x110 [ 25.118201] ? kobject_add+0x71/0x90 [ 25.118546] ? bd_register_pending_holders+0x2a/0x110 [ 25.118958] bd_register_pending_holders+0x2a/0x110 [ 25.119373] device_add_disk+0x209/0x370 [ 25.119732] ublk_ctrl_uring_cmd+0x405/0x730 [ 25.120109] ? rcu_read_lock_sched_held+0x3c/0x70 [ 25.120514] io_issue_sqe+0xfe/0x2ac0 [ 25.120863] io_submit_sqes+0x352/0x1820 [ 25.121228] ? rcu_read_lock_sched_held+0x3c/0x70 [ 25.121626] ? __do_sys_io_uring_enter+0x83e/0xdc0 [ 25.122028] ? find_held_lock+0x2b/0x80 [ 25.122390] ? __do_sys_io_uring_enter+0x848/0xdc0 [ 25.122791] __do_sys_io_uring_enter+0x848/0xdc0 [ 25.123190] ? syscall_enter_from_user_mode+0x20/0x70 [ 25.123606] ? syscall_enter_from_user_mode+0x20/0x70 [ 25.124024] do_syscall_64+0x37/0x80 [ 25.124383] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.124829] RIP: 0033:0x7f120a762af6 [ 25.125223] Code: 45 c1 41 89 c2 41 b9 08 00 00 00 41 83 ca 10 f6 87 d0 00 00 00 01 8b bf cc 00 00 00 44 0f 44 d0 45 31 c0c [ 25.126576] RSP: 002b:00007ffdcb3c5518 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa [ 25.127153] RAX: ffffffffffffffda RBX: 00000000013aef50 RCX: 00007f120a762af6 [ 25.127748] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000004 [ 25.128351] RBP: 000000000000000b R08: 0000000000000000 R09: 0000000000000008 [ 25.128956] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffdcb3c74a6 [ 25.129524] R13: 00000000013aef50 R14: 0000000000000000 R15: 00000000000003df [ 25.130121] </TASK> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220721153117.591394-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-21 23:31:17 +08:00
spinlock_t mm_lock;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
struct mm_struct *mm;
struct ublk_params params;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
struct completion completion;
unsigned int nr_queues_ready;
atomic_t nr_aborted_queues;
/*
* Our ubq->daemon may be killed without any notification, so
* monitor each queue's daemon periodically
*/
struct delayed_work monitor_work;
struct work_struct stop_work;
};
/* header of ublk_params */
struct ublk_params_header {
__u32 len;
__u32 types;
};
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
static dev_t ublk_chr_devt;
static struct class *ublk_chr_class;
static DEFINE_IDR(ublk_index_idr);
static DEFINE_SPINLOCK(ublk_idr_lock);
static wait_queue_head_t ublk_idr_wq; /* wait until one idr is freed */
static DEFINE_MUTEX(ublk_ctl_mutex);
static struct miscdevice ublk_misc;
static void ublk_dev_param_basic_apply(struct ublk_device *ub)
{
struct request_queue *q = ub->ub_disk->queue;
const struct ublk_param_basic *p = &ub->params.basic;
blk_queue_logical_block_size(q, 1 << p->logical_bs_shift);
blk_queue_physical_block_size(q, 1 << p->physical_bs_shift);
blk_queue_io_min(q, 1 << p->io_min_shift);
blk_queue_io_opt(q, 1 << p->io_opt_shift);
blk_queue_write_cache(q, p->attrs & UBLK_ATTR_VOLATILE_CACHE,
p->attrs & UBLK_ATTR_FUA);
if (p->attrs & UBLK_ATTR_ROTATIONAL)
blk_queue_flag_clear(QUEUE_FLAG_NONROT, q);
else
blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
blk_queue_max_hw_sectors(q, p->max_sectors);
blk_queue_chunk_sectors(q, p->chunk_sectors);
blk_queue_virt_boundary(q, p->virt_boundary_mask);
if (p->attrs & UBLK_ATTR_READ_ONLY)
set_disk_ro(ub->ub_disk, true);
set_capacity(ub->ub_disk, p->dev_sectors);
}
static void ublk_dev_param_discard_apply(struct ublk_device *ub)
{
struct request_queue *q = ub->ub_disk->queue;
const struct ublk_param_discard *p = &ub->params.discard;
q->limits.discard_alignment = p->discard_alignment;
q->limits.discard_granularity = p->discard_granularity;
blk_queue_max_discard_sectors(q, p->max_discard_sectors);
blk_queue_max_write_zeroes_sectors(q,
p->max_write_zeroes_sectors);
blk_queue_max_discard_segments(q, p->max_discard_segments);
}
static int ublk_validate_params(const struct ublk_device *ub)
{
/* basic param is the only one which must be set */
if (ub->params.types & UBLK_PARAM_TYPE_BASIC) {
const struct ublk_param_basic *p = &ub->params.basic;
if (p->logical_bs_shift > PAGE_SHIFT)
return -EINVAL;
if (p->logical_bs_shift > p->physical_bs_shift)
return -EINVAL;
if (p->max_sectors > (ub->dev_info.max_io_buf_bytes >> 9))
return -EINVAL;
} else
return -EINVAL;
if (ub->params.types & UBLK_PARAM_TYPE_DISCARD) {
const struct ublk_param_discard *p = &ub->params.discard;
/* So far, only support single segment discard */
if (p->max_discard_sectors && p->max_discard_segments != 1)
return -EINVAL;
if (!p->discard_granularity)
return -EINVAL;
}
return 0;
}
static int ublk_apply_params(struct ublk_device *ub)
{
if (!(ub->params.types & UBLK_PARAM_TYPE_BASIC))
return -EINVAL;
ublk_dev_param_basic_apply(ub);
if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
ublk_dev_param_discard_apply(ub);
return 0;
}
static inline bool ublk_can_use_task_work(const struct ublk_queue *ubq)
{
if (IS_BUILTIN(CONFIG_BLK_DEV_UBLK) &&
!(ubq->flags & UBLK_F_URING_CMD_COMP_IN_TASK))
return true;
return false;
}
static inline bool ublk_need_get_data(const struct ublk_queue *ubq)
{
if (ubq->flags & UBLK_F_NEED_GET_DATA)
return true;
return false;
}
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
static struct ublk_device *ublk_get_device(struct ublk_device *ub)
{
if (kobject_get_unless_zero(&ub->cdev_dev.kobj))
return ub;
return NULL;
}
static void ublk_put_device(struct ublk_device *ub)
{
put_device(&ub->cdev_dev);
}
static inline struct ublk_queue *ublk_get_queue(struct ublk_device *dev,
int qid)
{
return (struct ublk_queue *)&(dev->__queues[qid * dev->queue_size]);
}
static inline bool ublk_rq_has_data(const struct request *rq)
{
return rq->bio && bio_has_data(rq->bio);
}
static inline struct ublksrv_io_desc *ublk_get_iod(struct ublk_queue *ubq,
int tag)
{
return (struct ublksrv_io_desc *)
&(ubq->io_cmd_buf[tag * sizeof(struct ublksrv_io_desc)]);
}
static inline char *ublk_queue_cmd_buf(struct ublk_device *ub, int q_id)
{
return ublk_get_queue(ub, q_id)->io_cmd_buf;
}
static inline int ublk_queue_cmd_buf_size(struct ublk_device *ub, int q_id)
{
struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
return round_up(ubq->q_depth * sizeof(struct ublksrv_io_desc),
PAGE_SIZE);
}
static void ublk_free_disk(struct gendisk *disk)
{
struct ublk_device *ub = disk->private_data;
clear_bit(UB_STATE_USED, &ub->state);
put_device(&ub->cdev_dev);
}
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
static const struct block_device_operations ub_fops = {
.owner = THIS_MODULE,
.free_disk = ublk_free_disk,
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
};
#define UBLK_MAX_PIN_PAGES 32
struct ublk_map_data {
const struct ublk_queue *ubq;
const struct request *rq;
const struct ublk_io *io;
unsigned max_bytes;
};
struct ublk_io_iter {
struct page *pages[UBLK_MAX_PIN_PAGES];
unsigned pg_off; /* offset in the 1st page in pages */
int nr_pages; /* how many page pointers in pages */
struct bio *bio;
struct bvec_iter iter;
};
static inline unsigned ublk_copy_io_pages(struct ublk_io_iter *data,
unsigned max_bytes, bool to_vm)
{
const unsigned total = min_t(unsigned, max_bytes,
PAGE_SIZE - data->pg_off +
((data->nr_pages - 1) << PAGE_SHIFT));
unsigned done = 0;
unsigned pg_idx = 0;
while (done < total) {
struct bio_vec bv = bio_iter_iovec(data->bio, data->iter);
const unsigned int bytes = min3(bv.bv_len, total - done,
(unsigned)(PAGE_SIZE - data->pg_off));
void *bv_buf = bvec_kmap_local(&bv);
void *pg_buf = kmap_local_page(data->pages[pg_idx]);
if (to_vm)
memcpy(pg_buf + data->pg_off, bv_buf, bytes);
else
memcpy(bv_buf, pg_buf + data->pg_off, bytes);
kunmap_local(pg_buf);
kunmap_local(bv_buf);
/* advance page array */
data->pg_off += bytes;
if (data->pg_off == PAGE_SIZE) {
pg_idx += 1;
data->pg_off = 0;
}
done += bytes;
/* advance bio */
bio_advance_iter_single(data->bio, &data->iter, bytes);
if (!data->iter.bi_size) {
data->bio = data->bio->bi_next;
if (data->bio == NULL)
break;
data->iter = data->bio->bi_iter;
}
}
return done;
}
static inline int ublk_copy_user_pages(struct ublk_map_data *data,
bool to_vm)
{
const unsigned int gup_flags = to_vm ? FOLL_WRITE : 0;
const unsigned long start_vm = data->io->addr;
unsigned int done = 0;
struct ublk_io_iter iter = {
.pg_off = start_vm & (PAGE_SIZE - 1),
.bio = data->rq->bio,
.iter = data->rq->bio->bi_iter,
};
const unsigned int nr_pages = round_up(data->max_bytes +
(start_vm & (PAGE_SIZE - 1)), PAGE_SIZE) >> PAGE_SHIFT;
while (done < nr_pages) {
const unsigned to_pin = min_t(unsigned, UBLK_MAX_PIN_PAGES,
nr_pages - done);
unsigned i, len;
iter.nr_pages = get_user_pages_fast(start_vm +
(done << PAGE_SHIFT), to_pin, gup_flags,
iter.pages);
if (iter.nr_pages <= 0)
return done == 0 ? iter.nr_pages : done;
len = ublk_copy_io_pages(&iter, data->max_bytes, to_vm);
for (i = 0; i < iter.nr_pages; i++) {
if (to_vm)
set_page_dirty(iter.pages[i]);
put_page(iter.pages[i]);
}
data->max_bytes -= len;
done += iter.nr_pages;
}
return done;
}
static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req,
struct ublk_io *io)
{
const unsigned int rq_bytes = blk_rq_bytes(req);
/*
* no zero copy, we delay copy WRITE request data into ublksrv
* context and the big benefit is that pinning pages in current
* context is pretty fast, see ublk_pin_user_pages
*/
if (req_op(req) != REQ_OP_WRITE && req_op(req) != REQ_OP_FLUSH)
return rq_bytes;
if (ublk_rq_has_data(req)) {
struct ublk_map_data data = {
.ubq = ubq,
.rq = req,
.io = io,
.max_bytes = rq_bytes,
};
ublk_copy_user_pages(&data, true);
return rq_bytes - data.max_bytes;
}
return rq_bytes;
}
static int ublk_unmap_io(const struct ublk_queue *ubq,
const struct request *req,
struct ublk_io *io)
{
const unsigned int rq_bytes = blk_rq_bytes(req);
if (req_op(req) == REQ_OP_READ && ublk_rq_has_data(req)) {
struct ublk_map_data data = {
.ubq = ubq,
.rq = req,
.io = io,
.max_bytes = io->res,
};
WARN_ON_ONCE(io->res > rq_bytes);
ublk_copy_user_pages(&data, false);
return io->res - data.max_bytes;
}
return rq_bytes;
}
static inline unsigned int ublk_req_build_flags(struct request *req)
{
unsigned flags = 0;
if (req->cmd_flags & REQ_FAILFAST_DEV)
flags |= UBLK_IO_F_FAILFAST_DEV;
if (req->cmd_flags & REQ_FAILFAST_TRANSPORT)
flags |= UBLK_IO_F_FAILFAST_TRANSPORT;
if (req->cmd_flags & REQ_FAILFAST_DRIVER)
flags |= UBLK_IO_F_FAILFAST_DRIVER;
if (req->cmd_flags & REQ_META)
flags |= UBLK_IO_F_META;
if (req->cmd_flags & REQ_FUA)
flags |= UBLK_IO_F_FUA;
if (req->cmd_flags & REQ_NOUNMAP)
flags |= UBLK_IO_F_NOUNMAP;
if (req->cmd_flags & REQ_SWAP)
flags |= UBLK_IO_F_SWAP;
return flags;
}
static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
{
struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag);
struct ublk_io *io = &ubq->ios[req->tag];
u32 ublk_op;
switch (req_op(req)) {
case REQ_OP_READ:
ublk_op = UBLK_IO_OP_READ;
break;
case REQ_OP_WRITE:
ublk_op = UBLK_IO_OP_WRITE;
break;
case REQ_OP_FLUSH:
ublk_op = UBLK_IO_OP_FLUSH;
break;
case REQ_OP_DISCARD:
ublk_op = UBLK_IO_OP_DISCARD;
break;
case REQ_OP_WRITE_ZEROES:
ublk_op = UBLK_IO_OP_WRITE_ZEROES;
break;
default:
return BLK_STS_IOERR;
}
/* need to translate since kernel may change */
iod->op_flags = ublk_op | ublk_req_build_flags(req);
iod->nr_sectors = blk_rq_sectors(req);
iod->start_sector = blk_rq_pos(req);
iod->addr = io->addr;
return BLK_STS_OK;
}
static inline struct ublk_uring_cmd_pdu *ublk_get_uring_cmd_pdu(
struct io_uring_cmd *ioucmd)
{
return (struct ublk_uring_cmd_pdu *)&ioucmd->pdu;
}
static bool ubq_daemon_is_dying(struct ublk_queue *ubq)
{
return ubq->ubq_daemon->flags & PF_EXITING;
}
/* todo: handle partial completion */
static void ublk_complete_rq(struct request *req)
{
struct ublk_queue *ubq = req->mq_hctx->driver_data;
struct ublk_io *io = &ubq->ios[req->tag];
unsigned int unmapped_bytes;
/* failed read IO if nothing is read */
if (!io->res && req_op(req) == REQ_OP_READ)
io->res = -EIO;
if (io->res < 0) {
blk_mq_end_request(req, errno_to_blk_status(io->res));
return;
}
/*
* FLUSH or DISCARD usually won't return bytes returned, so end them
* directly.
*
* Both the two needn't unmap.
*/
if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE) {
blk_mq_end_request(req, BLK_STS_OK);
return;
}
/* for READ request, writing data in iod->addr to rq buffers */
unmapped_bytes = ublk_unmap_io(ubq, req, io);
/*
* Extremely impossible since we got data filled in just before
*
* Re-read simply for this unlikely case.
*/
if (unlikely(unmapped_bytes < io->res))
io->res = unmapped_bytes;
if (blk_update_request(req, BLK_STS_OK, io->res))
blk_mq_requeue_request(req, true);
else
__blk_mq_end_request(req, BLK_STS_OK);
}
/*
* __ublk_fail_req() may be called from abort context or ->ubq_daemon
* context during exiting, so lock is required.
*
* Also aborting may not be started yet, keep in mind that one failed
* request may be issued by block layer again.
*/
static void __ublk_fail_req(struct ublk_io *io, struct request *req)
{
WARN_ON_ONCE(io->flags & UBLK_IO_FLAG_ACTIVE);
if (!(io->flags & UBLK_IO_FLAG_ABORTED)) {
io->flags |= UBLK_IO_FLAG_ABORTED;
blk_mq_end_request(req, BLK_STS_IOERR);
}
}
static void ubq_complete_io_cmd(struct ublk_io *io, int res)
{
/* mark this cmd owned by ublksrv */
io->flags |= UBLK_IO_FLAG_OWNED_BY_SRV;
/*
* clear ACTIVE since we are done with this sqe/cmd slot
* We can only accept io cmd in case of being not active.
*/
io->flags &= ~UBLK_IO_FLAG_ACTIVE;
/* tell ublksrv one io request is coming */
io_uring_cmd_done(io->cmd, res, 0);
}
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
#define UBLK_REQUEUE_DELAY_MS 3
static inline void __ublk_rq_task_work(struct request *req)
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
{
struct ublk_queue *ubq = req->mq_hctx->driver_data;
struct ublk_device *ub = ubq->dev;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
int tag = req->tag;
struct ublk_io *io = &ubq->ios[tag];
bool task_exiting = current != ubq->ubq_daemon ||
(current->flags & PF_EXITING);
unsigned int mapped_bytes;
pr_devel("%s: complete: op %d, qid %d tag %d io_flags %x addr %llx\n",
__func__, io->cmd->cmd_op, ubq->q_id, req->tag, io->flags,
ublk_get_iod(ubq, req->tag)->addr);
if (unlikely(task_exiting)) {
blk_mq_end_request(req, BLK_STS_IOERR);
mod_delayed_work(system_wq, &ub->monitor_work, 0);
return;
}
if (ublk_need_get_data(ubq) &&
(req_op(req) == REQ_OP_WRITE ||
req_op(req) == REQ_OP_FLUSH)) {
/*
* We have not handled UBLK_IO_NEED_GET_DATA command yet,
* so immepdately pass UBLK_IO_RES_NEED_GET_DATA to ublksrv
* and notify it.
*/
if (!(io->flags & UBLK_IO_FLAG_NEED_GET_DATA)) {
io->flags |= UBLK_IO_FLAG_NEED_GET_DATA;
pr_devel("%s: need get data. op %d, qid %d tag %d io_flags %x\n",
__func__, io->cmd->cmd_op, ubq->q_id,
req->tag, io->flags);
ubq_complete_io_cmd(io, UBLK_IO_RES_NEED_GET_DATA);
return;
}
/*
* We have handled UBLK_IO_NEED_GET_DATA command,
* so clear UBLK_IO_FLAG_NEED_GET_DATA now and just
* do the copy work.
*/
io->flags &= ~UBLK_IO_FLAG_NEED_GET_DATA;
}
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
mapped_bytes = ublk_map_io(ubq, req, io);
/* partially mapped, update io descriptor */
if (unlikely(mapped_bytes != blk_rq_bytes(req))) {
/*
* Nothing mapped, retry until we succeed.
*
* We may never succeed in mapping any bytes here because
* of OOM. TODO: reserve one buffer with single page pinned
* for providing forward progress guarantee.
*/
if (unlikely(!mapped_bytes)) {
blk_mq_requeue_request(req, false);
blk_mq_delay_kick_requeue_list(req->q,
UBLK_REQUEUE_DELAY_MS);
return;
}
ublk_get_iod(ubq, req->tag)->nr_sectors =
mapped_bytes >> 9;
}
ubq_complete_io_cmd(io, UBLK_IO_RES_OK);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
}
static void ublk_rq_task_work_cb(struct io_uring_cmd *cmd)
{
struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd);
__ublk_rq_task_work(pdu->req);
}
static void ublk_rq_task_work_fn(struct callback_head *work)
{
struct ublk_rq_data *data = container_of(work,
struct ublk_rq_data, work);
struct request *req = blk_mq_rq_from_pdu(data);
__ublk_rq_task_work(req);
}
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
struct ublk_queue *ubq = hctx->driver_data;
struct request *rq = bd->rq;
blk_status_t res;
/* fill iod to slot in io cmd buffer */
res = ublk_setup_iod(ubq, rq);
if (unlikely(res != BLK_STS_OK))
return BLK_STS_IOERR;
blk_mq_start_request(bd->rq);
if (unlikely(ubq_daemon_is_dying(ubq))) {
fail:
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
mod_delayed_work(system_wq, &ubq->dev->monitor_work, 0);
return BLK_STS_IOERR;
}
if (ublk_can_use_task_work(ubq)) {
struct ublk_rq_data *data = blk_mq_rq_to_pdu(rq);
enum task_work_notify_mode notify_mode = bd->last ?
TWA_SIGNAL_NO_IPI : TWA_NONE;
if (task_work_add(ubq->ubq_daemon, &data->work, notify_mode))
goto fail;
} else {
struct io_uring_cmd *cmd = ubq->ios[rq->tag].cmd;
struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd);
pdu->req = rq;
io_uring_cmd_complete_in_task(cmd, ublk_rq_task_work_cb);
}
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
return BLK_STS_OK;
}
static void ublk_commit_rqs(struct blk_mq_hw_ctx *hctx)
{
struct ublk_queue *ubq = hctx->driver_data;
if (ublk_can_use_task_work(ubq))
__set_notify_signal(ubq->ubq_daemon);
}
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
static int ublk_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data,
unsigned int hctx_idx)
{
struct ublk_device *ub = driver_data;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
struct ublk_queue *ubq = ublk_get_queue(ub, hctx->queue_num);
hctx->driver_data = ubq;
return 0;
}
static int ublk_init_rq(struct blk_mq_tag_set *set, struct request *req,
unsigned int hctx_idx, unsigned int numa_node)
{
struct ublk_rq_data *data = blk_mq_rq_to_pdu(req);
init_task_work(&data->work, ublk_rq_task_work_fn);
return 0;
}
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
static const struct blk_mq_ops ublk_mq_ops = {
.queue_rq = ublk_queue_rq,
.commit_rqs = ublk_commit_rqs,
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
.init_hctx = ublk_init_hctx,
.init_request = ublk_init_rq,
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
};
static int ublk_ch_open(struct inode *inode, struct file *filp)
{
struct ublk_device *ub = container_of(inode->i_cdev,
struct ublk_device, cdev);
if (test_and_set_bit(UB_STATE_OPEN, &ub->state))
return -EBUSY;
filp->private_data = ub;
return 0;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
}
static int ublk_ch_release(struct inode *inode, struct file *filp)
{
struct ublk_device *ub = filp->private_data;
clear_bit(UB_STATE_OPEN, &ub->state);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
return 0;
}
/* map pre-allocated per-queue cmd buffer to ublksrv daemon */
static int ublk_ch_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct ublk_device *ub = filp->private_data;
size_t sz = vma->vm_end - vma->vm_start;
unsigned max_sz = UBLK_MAX_QUEUE_DEPTH * sizeof(struct ublksrv_io_desc);
unsigned long pfn, end, phys_off = vma->vm_pgoff << PAGE_SHIFT;
int q_id, ret = 0;
ublk_drv: fix lockdep warning ub->mutex is used to protecting reading and writing ub->mm, then the following lockdep warning is triggered. Fix it by using one dedicated spin lock for protecting ub->mm. [1] lockdep warning [ 25.046186] ====================================================== [ 25.048886] WARNING: possible circular locking dependency detected [ 25.051610] 5.19.0-rc4_for-v5.20+ #149 Not tainted [ 25.053665] ------------------------------------------------------ [ 25.056334] ublk/989 is trying to acquire lock: [ 25.058296] ffff975d0329a918 (&disk->open_mutex){+.+.}-{3:3}, at: bd_register_pending_holders+0x2a/0x110 [ 25.063678] [ 25.063678] but task is already holding lock: [ 25.066246] ffff975d1df59708 (&ub->mutex){+.+.}-{3:3}, at: ublk_ctrl_uring_cmd+0x2df/0x730 [ 25.069423] [ 25.069423] which lock already depends on the new lock. [ 25.069423] [ 25.072603] [ 25.072603] the existing dependency chain (in reverse order) is: [ 25.074908] [ 25.074908] -> #3 (&ub->mutex){+.+.}-{3:3}: [ 25.076386] __mutex_lock+0x93/0x870 [ 25.077470] ublk_ch_mmap+0x3a/0x140 [ 25.078494] mmap_region+0x375/0x5a0 [ 25.079386] do_mmap+0x33a/0x530 [ 25.080168] vm_mmap_pgoff+0xb9/0x150 [ 25.080979] ksys_mmap_pgoff+0x184/0x1f0 [ 25.081838] do_syscall_64+0x37/0x80 [ 25.082653] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.083730] [ 25.083730] -> #2 (&mm->mmap_lock#2){++++}-{3:3}: [ 25.084707] __might_fault+0x55/0x80 [ 25.085344] _copy_from_user+0x1e/0xa0 [ 25.086020] get_sg_io_hdr+0x26/0xb0 [ 25.086651] scsi_ioctl+0x42f/0x960 [ 25.087267] sr_block_ioctl+0xe8/0x100 [ 25.087734] blkdev_ioctl+0x134/0x2b0 [ 25.088196] __x64_sys_ioctl+0x8a/0xc0 [ 25.088677] do_syscall_64+0x37/0x80 [ 25.089044] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.089548] [ 25.089548] -> #1 (&cd->lock){+.+.}-{3:3}: [ 25.090072] __mutex_lock+0x93/0x870 [ 25.090452] sr_block_open+0x64/0xe0 [ 25.090837] blkdev_get_whole+0x26/0x90 [ 25.091445] blkdev_get_by_dev.part.0+0x1ce/0x2f0 [ 25.092203] blkdev_open+0x52/0x90 [ 25.092617] do_dentry_open+0x1ca/0x360 [ 25.093499] path_openat+0x78d/0xcb0 [ 25.094136] do_filp_open+0xa1/0x130 [ 25.094759] do_sys_openat2+0x76/0x130 [ 25.095454] __x64_sys_openat+0x5c/0x70 [ 25.096078] do_syscall_64+0x37/0x80 [ 25.096637] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.097304] [ 25.097304] -> #0 (&disk->open_mutex){+.+.}-{3:3}: [ 25.098229] __lock_acquire+0x12e2/0x1f90 [ 25.098789] lock_acquire+0xbf/0x2c0 [ 25.099256] __mutex_lock+0x93/0x870 [ 25.099706] bd_register_pending_holders+0x2a/0x110 [ 25.100246] device_add_disk+0x209/0x370 [ 25.100712] ublk_ctrl_uring_cmd+0x405/0x730 [ 25.101205] io_issue_sqe+0xfe/0x2ac0 [ 25.101665] io_submit_sqes+0x352/0x1820 [ 25.102131] __do_sys_io_uring_enter+0x848/0xdc0 [ 25.102646] do_syscall_64+0x37/0x80 [ 25.103087] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.103640] [ 25.103640] other info that might help us debug this: [ 25.103640] [ 25.104549] Chain exists of: [ 25.104549] &disk->open_mutex --> &mm->mmap_lock#2 --> &ub->mutex [ 25.104549] [ 25.105611] Possible unsafe locking scenario: [ 25.105611] [ 25.106258] CPU0 CPU1 [ 25.106677] ---- ---- [ 25.107100] lock(&ub->mutex); [ 25.107446] lock(&mm->mmap_lock#2); [ 25.108045] lock(&ub->mutex); [ 25.108802] lock(&disk->open_mutex); [ 25.109265] [ 25.109265] *** DEADLOCK *** [ 25.109265] [ 25.110117] 2 locks held by ublk/989: [ 25.110490] #0: ffff975d07bbf8a8 (&ctx->uring_lock){+.+.}-{3:3}, at: __do_sys_io_uring_enter+0x83e/0xdc0 [ 25.111249] #1: ffff975d1df59708 (&ub->mutex){+.+.}-{3:3}, at: ublk_ctrl_uring_cmd+0x2df/0x730 [ 25.111943] [ 25.111943] stack backtrace: [ 25.112557] CPU: 2 PID: 989 Comm: ublk Not tainted 5.19.0-rc4_for-v5.20+ #149 [ 25.113137] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-1.fc33 04/01/2014 [ 25.113792] Call Trace: [ 25.114130] <TASK> [ 25.114417] dump_stack_lvl+0x71/0xa0 [ 25.114771] check_noncircular+0xdf/0x100 [ 25.115137] ? register_lock_class+0x38/0x470 [ 25.115524] __lock_acquire+0x12e2/0x1f90 [ 25.115887] ? find_held_lock+0x2b/0x80 [ 25.116244] lock_acquire+0xbf/0x2c0 [ 25.116590] ? bd_register_pending_holders+0x2a/0x110 [ 25.117009] __mutex_lock+0x93/0x870 [ 25.117362] ? bd_register_pending_holders+0x2a/0x110 [ 25.117780] ? bd_register_pending_holders+0x2a/0x110 [ 25.118201] ? kobject_add+0x71/0x90 [ 25.118546] ? bd_register_pending_holders+0x2a/0x110 [ 25.118958] bd_register_pending_holders+0x2a/0x110 [ 25.119373] device_add_disk+0x209/0x370 [ 25.119732] ublk_ctrl_uring_cmd+0x405/0x730 [ 25.120109] ? rcu_read_lock_sched_held+0x3c/0x70 [ 25.120514] io_issue_sqe+0xfe/0x2ac0 [ 25.120863] io_submit_sqes+0x352/0x1820 [ 25.121228] ? rcu_read_lock_sched_held+0x3c/0x70 [ 25.121626] ? __do_sys_io_uring_enter+0x83e/0xdc0 [ 25.122028] ? find_held_lock+0x2b/0x80 [ 25.122390] ? __do_sys_io_uring_enter+0x848/0xdc0 [ 25.122791] __do_sys_io_uring_enter+0x848/0xdc0 [ 25.123190] ? syscall_enter_from_user_mode+0x20/0x70 [ 25.123606] ? syscall_enter_from_user_mode+0x20/0x70 [ 25.124024] do_syscall_64+0x37/0x80 [ 25.124383] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.124829] RIP: 0033:0x7f120a762af6 [ 25.125223] Code: 45 c1 41 89 c2 41 b9 08 00 00 00 41 83 ca 10 f6 87 d0 00 00 00 01 8b bf cc 00 00 00 44 0f 44 d0 45 31 c0c [ 25.126576] RSP: 002b:00007ffdcb3c5518 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa [ 25.127153] RAX: ffffffffffffffda RBX: 00000000013aef50 RCX: 00007f120a762af6 [ 25.127748] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000004 [ 25.128351] RBP: 000000000000000b R08: 0000000000000000 R09: 0000000000000008 [ 25.128956] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffdcb3c74a6 [ 25.129524] R13: 00000000013aef50 R14: 0000000000000000 R15: 00000000000003df [ 25.130121] </TASK> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220721153117.591394-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-21 23:31:17 +08:00
spin_lock(&ub->mm_lock);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
if (!ub->mm)
ub->mm = current->mm;
if (current->mm != ub->mm)
ret = -EINVAL;
ublk_drv: fix lockdep warning ub->mutex is used to protecting reading and writing ub->mm, then the following lockdep warning is triggered. Fix it by using one dedicated spin lock for protecting ub->mm. [1] lockdep warning [ 25.046186] ====================================================== [ 25.048886] WARNING: possible circular locking dependency detected [ 25.051610] 5.19.0-rc4_for-v5.20+ #149 Not tainted [ 25.053665] ------------------------------------------------------ [ 25.056334] ublk/989 is trying to acquire lock: [ 25.058296] ffff975d0329a918 (&disk->open_mutex){+.+.}-{3:3}, at: bd_register_pending_holders+0x2a/0x110 [ 25.063678] [ 25.063678] but task is already holding lock: [ 25.066246] ffff975d1df59708 (&ub->mutex){+.+.}-{3:3}, at: ublk_ctrl_uring_cmd+0x2df/0x730 [ 25.069423] [ 25.069423] which lock already depends on the new lock. [ 25.069423] [ 25.072603] [ 25.072603] the existing dependency chain (in reverse order) is: [ 25.074908] [ 25.074908] -> #3 (&ub->mutex){+.+.}-{3:3}: [ 25.076386] __mutex_lock+0x93/0x870 [ 25.077470] ublk_ch_mmap+0x3a/0x140 [ 25.078494] mmap_region+0x375/0x5a0 [ 25.079386] do_mmap+0x33a/0x530 [ 25.080168] vm_mmap_pgoff+0xb9/0x150 [ 25.080979] ksys_mmap_pgoff+0x184/0x1f0 [ 25.081838] do_syscall_64+0x37/0x80 [ 25.082653] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.083730] [ 25.083730] -> #2 (&mm->mmap_lock#2){++++}-{3:3}: [ 25.084707] __might_fault+0x55/0x80 [ 25.085344] _copy_from_user+0x1e/0xa0 [ 25.086020] get_sg_io_hdr+0x26/0xb0 [ 25.086651] scsi_ioctl+0x42f/0x960 [ 25.087267] sr_block_ioctl+0xe8/0x100 [ 25.087734] blkdev_ioctl+0x134/0x2b0 [ 25.088196] __x64_sys_ioctl+0x8a/0xc0 [ 25.088677] do_syscall_64+0x37/0x80 [ 25.089044] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.089548] [ 25.089548] -> #1 (&cd->lock){+.+.}-{3:3}: [ 25.090072] __mutex_lock+0x93/0x870 [ 25.090452] sr_block_open+0x64/0xe0 [ 25.090837] blkdev_get_whole+0x26/0x90 [ 25.091445] blkdev_get_by_dev.part.0+0x1ce/0x2f0 [ 25.092203] blkdev_open+0x52/0x90 [ 25.092617] do_dentry_open+0x1ca/0x360 [ 25.093499] path_openat+0x78d/0xcb0 [ 25.094136] do_filp_open+0xa1/0x130 [ 25.094759] do_sys_openat2+0x76/0x130 [ 25.095454] __x64_sys_openat+0x5c/0x70 [ 25.096078] do_syscall_64+0x37/0x80 [ 25.096637] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.097304] [ 25.097304] -> #0 (&disk->open_mutex){+.+.}-{3:3}: [ 25.098229] __lock_acquire+0x12e2/0x1f90 [ 25.098789] lock_acquire+0xbf/0x2c0 [ 25.099256] __mutex_lock+0x93/0x870 [ 25.099706] bd_register_pending_holders+0x2a/0x110 [ 25.100246] device_add_disk+0x209/0x370 [ 25.100712] ublk_ctrl_uring_cmd+0x405/0x730 [ 25.101205] io_issue_sqe+0xfe/0x2ac0 [ 25.101665] io_submit_sqes+0x352/0x1820 [ 25.102131] __do_sys_io_uring_enter+0x848/0xdc0 [ 25.102646] do_syscall_64+0x37/0x80 [ 25.103087] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.103640] [ 25.103640] other info that might help us debug this: [ 25.103640] [ 25.104549] Chain exists of: [ 25.104549] &disk->open_mutex --> &mm->mmap_lock#2 --> &ub->mutex [ 25.104549] [ 25.105611] Possible unsafe locking scenario: [ 25.105611] [ 25.106258] CPU0 CPU1 [ 25.106677] ---- ---- [ 25.107100] lock(&ub->mutex); [ 25.107446] lock(&mm->mmap_lock#2); [ 25.108045] lock(&ub->mutex); [ 25.108802] lock(&disk->open_mutex); [ 25.109265] [ 25.109265] *** DEADLOCK *** [ 25.109265] [ 25.110117] 2 locks held by ublk/989: [ 25.110490] #0: ffff975d07bbf8a8 (&ctx->uring_lock){+.+.}-{3:3}, at: __do_sys_io_uring_enter+0x83e/0xdc0 [ 25.111249] #1: ffff975d1df59708 (&ub->mutex){+.+.}-{3:3}, at: ublk_ctrl_uring_cmd+0x2df/0x730 [ 25.111943] [ 25.111943] stack backtrace: [ 25.112557] CPU: 2 PID: 989 Comm: ublk Not tainted 5.19.0-rc4_for-v5.20+ #149 [ 25.113137] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-1.fc33 04/01/2014 [ 25.113792] Call Trace: [ 25.114130] <TASK> [ 25.114417] dump_stack_lvl+0x71/0xa0 [ 25.114771] check_noncircular+0xdf/0x100 [ 25.115137] ? register_lock_class+0x38/0x470 [ 25.115524] __lock_acquire+0x12e2/0x1f90 [ 25.115887] ? find_held_lock+0x2b/0x80 [ 25.116244] lock_acquire+0xbf/0x2c0 [ 25.116590] ? bd_register_pending_holders+0x2a/0x110 [ 25.117009] __mutex_lock+0x93/0x870 [ 25.117362] ? bd_register_pending_holders+0x2a/0x110 [ 25.117780] ? bd_register_pending_holders+0x2a/0x110 [ 25.118201] ? kobject_add+0x71/0x90 [ 25.118546] ? bd_register_pending_holders+0x2a/0x110 [ 25.118958] bd_register_pending_holders+0x2a/0x110 [ 25.119373] device_add_disk+0x209/0x370 [ 25.119732] ublk_ctrl_uring_cmd+0x405/0x730 [ 25.120109] ? rcu_read_lock_sched_held+0x3c/0x70 [ 25.120514] io_issue_sqe+0xfe/0x2ac0 [ 25.120863] io_submit_sqes+0x352/0x1820 [ 25.121228] ? rcu_read_lock_sched_held+0x3c/0x70 [ 25.121626] ? __do_sys_io_uring_enter+0x83e/0xdc0 [ 25.122028] ? find_held_lock+0x2b/0x80 [ 25.122390] ? __do_sys_io_uring_enter+0x848/0xdc0 [ 25.122791] __do_sys_io_uring_enter+0x848/0xdc0 [ 25.123190] ? syscall_enter_from_user_mode+0x20/0x70 [ 25.123606] ? syscall_enter_from_user_mode+0x20/0x70 [ 25.124024] do_syscall_64+0x37/0x80 [ 25.124383] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 25.124829] RIP: 0033:0x7f120a762af6 [ 25.125223] Code: 45 c1 41 89 c2 41 b9 08 00 00 00 41 83 ca 10 f6 87 d0 00 00 00 01 8b bf cc 00 00 00 44 0f 44 d0 45 31 c0c [ 25.126576] RSP: 002b:00007ffdcb3c5518 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa [ 25.127153] RAX: ffffffffffffffda RBX: 00000000013aef50 RCX: 00007f120a762af6 [ 25.127748] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000004 [ 25.128351] RBP: 000000000000000b R08: 0000000000000000 R09: 0000000000000008 [ 25.128956] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffdcb3c74a6 [ 25.129524] R13: 00000000013aef50 R14: 0000000000000000 R15: 00000000000003df [ 25.130121] </TASK> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220721153117.591394-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-21 23:31:17 +08:00
spin_unlock(&ub->mm_lock);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
if (ret)
return ret;
if (vma->vm_flags & VM_WRITE)
return -EPERM;
end = UBLKSRV_CMD_BUF_OFFSET + ub->dev_info.nr_hw_queues * max_sz;
if (phys_off < UBLKSRV_CMD_BUF_OFFSET || phys_off >= end)
return -EINVAL;
q_id = (phys_off - UBLKSRV_CMD_BUF_OFFSET) / max_sz;
pr_devel("%s: qid %d, pid %d, addr %lx pg_off %lx sz %lu\n",
__func__, q_id, current->pid, vma->vm_start,
phys_off, (unsigned long)sz);
if (sz != ublk_queue_cmd_buf_size(ub, q_id))
return -EINVAL;
pfn = virt_to_phys(ublk_queue_cmd_buf(ub, q_id)) >> PAGE_SHIFT;
return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
}
static void ublk_commit_completion(struct ublk_device *ub,
struct ublksrv_io_cmd *ub_cmd)
{
u32 qid = ub_cmd->q_id, tag = ub_cmd->tag;
struct ublk_queue *ubq = ublk_get_queue(ub, qid);
struct ublk_io *io = &ubq->ios[tag];
struct request *req;
/* now this cmd slot is owned by nbd driver */
io->flags &= ~UBLK_IO_FLAG_OWNED_BY_SRV;
io->res = ub_cmd->result;
/* find the io request and complete */
req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag);
if (req && likely(!blk_should_fake_timeout(req->q)))
ublk_complete_rq(req);
}
/*
* When ->ubq_daemon is exiting, either new request is ended immediately,
* or any queued io command is drained, so it is safe to abort queue
* lockless
*/
static void ublk_abort_queue(struct ublk_device *ub, struct ublk_queue *ubq)
{
int i;
if (!ublk_get_device(ub))
return;
for (i = 0; i < ubq->q_depth; i++) {
struct ublk_io *io = &ubq->ios[i];
if (!(io->flags & UBLK_IO_FLAG_ACTIVE)) {
struct request *rq;
/*
* Either we fail the request or ublk_rq_task_work_fn
* will do it
*/
rq = blk_mq_tag_to_rq(ub->tag_set.tags[ubq->q_id], i);
if (rq)
__ublk_fail_req(io, rq);
}
}
ublk_put_device(ub);
}
static void ublk_daemon_monitor_work(struct work_struct *work)
{
struct ublk_device *ub =
container_of(work, struct ublk_device, monitor_work.work);
int i;
for (i = 0; i < ub->dev_info.nr_hw_queues; i++) {
struct ublk_queue *ubq = ublk_get_queue(ub, i);
if (ubq_daemon_is_dying(ubq)) {
schedule_work(&ub->stop_work);
/* abort queue is for making forward progress */
ublk_abort_queue(ub, ubq);
}
}
/*
* We can't schedule monitor work after ublk_remove() is started.
*
* No need ub->mutex, monitor work are canceled after state is marked
* as DEAD, so DEAD state is observed reliably.
*/
if (ub->dev_info.state != UBLK_S_DEV_DEAD)
schedule_delayed_work(&ub->monitor_work,
UBLK_DAEMON_MONITOR_PERIOD);
}
static inline bool ublk_queue_ready(struct ublk_queue *ubq)
{
return ubq->nr_io_ready == ubq->q_depth;
}
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
static void ublk_cancel_queue(struct ublk_queue *ubq)
{
int i;
if (!ublk_queue_ready(ubq))
return;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
for (i = 0; i < ubq->q_depth; i++) {
struct ublk_io *io = &ubq->ios[i];
if (io->flags & UBLK_IO_FLAG_ACTIVE)
io_uring_cmd_done(io->cmd, UBLK_IO_RES_ABORT, 0);
}
/* all io commands are canceled */
ubq->nr_io_ready = 0;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
}
/* Cancel all pending commands, must be called after del_gendisk() returns */
static void ublk_cancel_dev(struct ublk_device *ub)
{
int i;
for (i = 0; i < ub->dev_info.nr_hw_queues; i++)
ublk_cancel_queue(ublk_get_queue(ub, i));
}
static void ublk_stop_dev(struct ublk_device *ub)
{
mutex_lock(&ub->mutex);
if (ub->dev_info.state != UBLK_S_DEV_LIVE)
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
goto unlock;
del_gendisk(ub->ub_disk);
ub->dev_info.state = UBLK_S_DEV_DEAD;
ub->dev_info.ublksrv_pid = -1;
put_disk(ub->ub_disk);
ub->ub_disk = NULL;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
unlock:
ublk_cancel_dev(ub);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
mutex_unlock(&ub->mutex);
cancel_delayed_work_sync(&ub->monitor_work);
}
/* device can only be started after all IOs are ready */
static void ublk_mark_io_ready(struct ublk_device *ub, struct ublk_queue *ubq)
{
mutex_lock(&ub->mutex);
ubq->nr_io_ready++;
if (ublk_queue_ready(ubq)) {
ubq->ubq_daemon = current;
get_task_struct(ubq->ubq_daemon);
ub->nr_queues_ready++;
}
if (ub->nr_queues_ready == ub->dev_info.nr_hw_queues)
complete_all(&ub->completion);
mutex_unlock(&ub->mutex);
}
static void ublk_handle_need_get_data(struct ublk_device *ub, int q_id,
int tag, struct io_uring_cmd *cmd)
{
struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
struct request *req = blk_mq_tag_to_rq(ub->tag_set.tags[q_id], tag);
if (ublk_can_use_task_work(ubq)) {
struct ublk_rq_data *data = blk_mq_rq_to_pdu(req);
/* should not fail since we call it just in ubq->ubq_daemon */
task_work_add(ubq->ubq_daemon, &data->work, TWA_SIGNAL_NO_IPI);
} else {
struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd);
pdu->req = req;
io_uring_cmd_complete_in_task(cmd, ublk_rq_task_work_cb);
}
}
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
{
struct ublksrv_io_cmd *ub_cmd = (struct ublksrv_io_cmd *)cmd->cmd;
struct ublk_device *ub = cmd->file->private_data;
struct ublk_queue *ubq;
struct ublk_io *io;
u32 cmd_op = cmd->cmd_op;
unsigned tag = ub_cmd->tag;
int ret = -EINVAL;
pr_devel("%s: received: cmd op %d queue %d tag %d result %d\n",
__func__, cmd->cmd_op, ub_cmd->q_id, tag,
ub_cmd->result);
if (!(issue_flags & IO_URING_F_SQE128))
goto out;
if (ub_cmd->q_id >= ub->dev_info.nr_hw_queues)
goto out;
ubq = ublk_get_queue(ub, ub_cmd->q_id);
if (!ubq || ub_cmd->q_id != ubq->q_id)
goto out;
if (ubq->ubq_daemon && ubq->ubq_daemon != current)
goto out;
if (tag >= ubq->q_depth)
goto out;
io = &ubq->ios[tag];
/* there is pending io cmd, something must be wrong */
if (io->flags & UBLK_IO_FLAG_ACTIVE) {
ret = -EBUSY;
goto out;
}
/*
* ensure that the user issues UBLK_IO_NEED_GET_DATA
* iff the driver have set the UBLK_IO_FLAG_NEED_GET_DATA.
*/
if ((!!(io->flags & UBLK_IO_FLAG_NEED_GET_DATA))
^ (cmd_op == UBLK_IO_NEED_GET_DATA))
goto out;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
switch (cmd_op) {
case UBLK_IO_FETCH_REQ:
/* UBLK_IO_FETCH_REQ is only allowed before queue is setup */
if (ublk_queue_ready(ubq)) {
ret = -EBUSY;
goto out;
}
/*
* The io is being handled by server, so COMMIT_RQ is expected
* instead of FETCH_REQ
*/
if (io->flags & UBLK_IO_FLAG_OWNED_BY_SRV)
goto out;
/* FETCH_RQ has to provide IO buffer */
if (!ub_cmd->addr)
goto out;
io->cmd = cmd;
io->flags |= UBLK_IO_FLAG_ACTIVE;
io->addr = ub_cmd->addr;
ublk_mark_io_ready(ub, ubq);
break;
case UBLK_IO_COMMIT_AND_FETCH_REQ:
/* FETCH_RQ has to provide IO buffer */
if (!ub_cmd->addr)
goto out;
if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
goto out;
io->addr = ub_cmd->addr;
io->flags |= UBLK_IO_FLAG_ACTIVE;
io->cmd = cmd;
ublk_commit_completion(ub, ub_cmd);
break;
case UBLK_IO_NEED_GET_DATA:
if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
goto out;
io->addr = ub_cmd->addr;
io->cmd = cmd;
io->flags |= UBLK_IO_FLAG_ACTIVE;
ublk_handle_need_get_data(ub, ub_cmd->q_id, ub_cmd->tag, cmd);
break;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
default:
goto out;
}
return -EIOCBQUEUED;
out:
io_uring_cmd_done(cmd, ret, 0);
pr_devel("%s: complete: cmd op %d, tag %d ret %x io_flags %x\n",
__func__, cmd_op, tag, ret, io->flags);
return -EIOCBQUEUED;
}
static const struct file_operations ublk_ch_fops = {
.owner = THIS_MODULE,
.open = ublk_ch_open,
.release = ublk_ch_release,
.llseek = no_llseek,
.uring_cmd = ublk_ch_uring_cmd,
.mmap = ublk_ch_mmap,
};
static void ublk_deinit_queue(struct ublk_device *ub, int q_id)
{
int size = ublk_queue_cmd_buf_size(ub, q_id);
struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
if (ubq->ubq_daemon)
put_task_struct(ubq->ubq_daemon);
if (ubq->io_cmd_buf)
free_pages((unsigned long)ubq->io_cmd_buf, get_order(size));
}
static int ublk_init_queue(struct ublk_device *ub, int q_id)
{
struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO;
void *ptr;
int size;
ubq->flags = ub->dev_info.flags;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
ubq->q_id = q_id;
ubq->q_depth = ub->dev_info.queue_depth;
size = ublk_queue_cmd_buf_size(ub, q_id);
ptr = (void *) __get_free_pages(gfp_flags, get_order(size));
if (!ptr)
return -ENOMEM;
ubq->io_cmd_buf = ptr;
ubq->dev = ub;
return 0;
}
static void ublk_deinit_queues(struct ublk_device *ub)
{
int nr_queues = ub->dev_info.nr_hw_queues;
int i;
if (!ub->__queues)
return;
for (i = 0; i < nr_queues; i++)
ublk_deinit_queue(ub, i);
kfree(ub->__queues);
}
static int ublk_init_queues(struct ublk_device *ub)
{
int nr_queues = ub->dev_info.nr_hw_queues;
int depth = ub->dev_info.queue_depth;
int ubq_size = sizeof(struct ublk_queue) + depth * sizeof(struct ublk_io);
int i, ret = -ENOMEM;
ub->queue_size = ubq_size;
ub->__queues = kcalloc(nr_queues, ubq_size, GFP_KERNEL);
if (!ub->__queues)
return ret;
for (i = 0; i < nr_queues; i++) {
if (ublk_init_queue(ub, i))
goto fail;
}
init_completion(&ub->completion);
return 0;
fail:
ublk_deinit_queues(ub);
return ret;
}
static int ublk_alloc_dev_number(struct ublk_device *ub, int idx)
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
{
int i = idx;
int err;
spin_lock(&ublk_idr_lock);
/* allocate id, if @id >= 0, we're requesting that specific id */
if (i >= 0) {
err = idr_alloc(&ublk_index_idr, ub, i, i + 1, GFP_NOWAIT);
if (err == -ENOSPC)
err = -EEXIST;
} else {
err = idr_alloc(&ublk_index_idr, ub, 0, 0, GFP_NOWAIT);
}
spin_unlock(&ublk_idr_lock);
if (err >= 0)
ub->ub_number = err;
return err;
}
static void ublk_free_dev_number(struct ublk_device *ub)
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
{
spin_lock(&ublk_idr_lock);
idr_remove(&ublk_index_idr, ub->ub_number);
wake_up_all(&ublk_idr_wq);
spin_unlock(&ublk_idr_lock);
}
static void ublk_cdev_rel(struct device *dev)
{
struct ublk_device *ub = container_of(dev, struct ublk_device, cdev_dev);
blk_mq_free_tag_set(&ub->tag_set);
ublk_deinit_queues(ub);
ublk_free_dev_number(ub);
mutex_destroy(&ub->mutex);
kfree(ub);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
}
static int ublk_add_chdev(struct ublk_device *ub)
{
struct device *dev = &ub->cdev_dev;
int minor = ub->ub_number;
int ret;
dev->parent = ublk_misc.this_device;
dev->devt = MKDEV(MAJOR(ublk_chr_devt), minor);
dev->class = ublk_chr_class;
dev->release = ublk_cdev_rel;
device_initialize(dev);
ret = dev_set_name(dev, "ublkc%d", minor);
if (ret)
goto fail;
cdev_init(&ub->cdev, &ublk_ch_fops);
ret = cdev_device_add(&ub->cdev, dev);
if (ret)
goto fail;
return 0;
fail:
put_device(dev);
return ret;
}
static void ublk_stop_work_fn(struct work_struct *work)
{
struct ublk_device *ub =
container_of(work, struct ublk_device, stop_work);
ublk_stop_dev(ub);
}
/* align max io buffer size with PAGE_SIZE */
static void ublk_align_max_io_size(struct ublk_device *ub)
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
{
unsigned int max_io_bytes = ub->dev_info.max_io_buf_bytes;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
ub->dev_info.max_io_buf_bytes =
round_down(max_io_bytes, PAGE_SIZE);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
}
static int ublk_add_tag_set(struct ublk_device *ub)
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
{
ub->tag_set.ops = &ublk_mq_ops;
ub->tag_set.nr_hw_queues = ub->dev_info.nr_hw_queues;
ub->tag_set.queue_depth = ub->dev_info.queue_depth;
ub->tag_set.numa_node = NUMA_NO_NODE;
ub->tag_set.cmd_size = sizeof(struct ublk_rq_data);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
ub->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
ub->tag_set.driver_data = ub;
return blk_mq_alloc_tag_set(&ub->tag_set);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
}
static void ublk_remove(struct ublk_device *ub)
{
ublk_stop_dev(ub);
cancel_work_sync(&ub->stop_work);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
cdev_device_del(&ub->cdev, &ub->cdev_dev);
put_device(&ub->cdev_dev);
}
static struct ublk_device *ublk_get_device_from_id(int idx)
{
struct ublk_device *ub = NULL;
if (idx < 0)
return NULL;
spin_lock(&ublk_idr_lock);
ub = idr_find(&ublk_index_idr, idx);
if (ub)
ub = ublk_get_device(ub);
spin_unlock(&ublk_idr_lock);
return ub;
}
static int ublk_ctrl_start_dev(struct io_uring_cmd *cmd)
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
{
struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
int ublksrv_pid = (int)header->data[0];
struct ublk_device *ub;
struct gendisk *disk;
int ret = -EINVAL;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
if (ublksrv_pid <= 0)
return -EINVAL;
ub = ublk_get_device_from_id(header->dev_id);
if (!ub)
return -EINVAL;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
wait_for_completion_interruptible(&ub->completion);
schedule_delayed_work(&ub->monitor_work, UBLK_DAEMON_MONITOR_PERIOD);
mutex_lock(&ub->mutex);
if (ub->dev_info.state == UBLK_S_DEV_LIVE ||
test_bit(UB_STATE_USED, &ub->state)) {
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
ret = -EEXIST;
goto out_unlock;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
}
disk = blk_mq_alloc_disk(&ub->tag_set, ub);
if (IS_ERR(disk)) {
ret = PTR_ERR(disk);
goto out_unlock;
}
sprintf(disk->disk_name, "ublkb%d", ub->ub_number);
disk->fops = &ub_fops;
disk->private_data = ub;
ub->dev_info.ublksrv_pid = ublksrv_pid;
ub->ub_disk = disk;
ret = ublk_apply_params(ub);
if (ret)
goto out_put_disk;
get_device(&ub->cdev_dev);
ret = add_disk(disk);
if (ret) {
/*
* Has to drop the reference since ->free_disk won't be
* called in case of add_disk failure.
*/
ublk_put_device(ub);
goto out_put_disk;
}
set_bit(UB_STATE_USED, &ub->state);
ub->dev_info.state = UBLK_S_DEV_LIVE;
out_put_disk:
if (ret)
put_disk(disk);
out_unlock:
mutex_unlock(&ub->mutex);
ublk_put_device(ub);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
return ret;
}
static int ublk_ctrl_get_queue_affinity(struct io_uring_cmd *cmd)
{
struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
void __user *argp = (void __user *)(unsigned long)header->addr;
struct ublk_device *ub;
cpumask_var_t cpumask;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
unsigned long queue;
unsigned int retlen;
unsigned int i;
int ret = -EINVAL;
if (header->len * BITS_PER_BYTE < nr_cpu_ids)
return -EINVAL;
if (header->len & (sizeof(unsigned long)-1))
return -EINVAL;
if (!header->addr)
return -EINVAL;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
ub = ublk_get_device_from_id(header->dev_id);
if (!ub)
return -EINVAL;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
queue = header->data[0];
if (queue >= ub->dev_info.nr_hw_queues)
goto out_put_device;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
ret = -ENOMEM;
if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL))
goto out_put_device;
for_each_possible_cpu(i) {
if (ub->tag_set.map[HCTX_TYPE_DEFAULT].mq_map[i] == queue)
cpumask_set_cpu(i, cpumask);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
}
ret = -EFAULT;
retlen = min_t(unsigned short, header->len, cpumask_size());
if (copy_to_user(argp, cpumask, retlen))
goto out_free_cpumask;
if (retlen != header->len &&
clear_user(argp + retlen, header->len - retlen))
goto out_free_cpumask;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
ret = 0;
out_free_cpumask:
free_cpumask_var(cpumask);
out_put_device:
ublk_put_device(ub);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
return ret;
}
static inline void ublk_dump_dev_info(struct ublksrv_ctrl_dev_info *info)
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
{
pr_devel("%s: dev id %d flags %llx\n", __func__,
info->dev_id, info->flags);
pr_devel("\t nr_hw_queues %d queue_depth %d\n",
info->nr_hw_queues, info->queue_depth);
}
static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
{
struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
void __user *argp = (void __user *)(unsigned long)header->addr;
struct ublksrv_ctrl_dev_info info;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
struct ublk_device *ub;
int ret = -EINVAL;
if (header->len < sizeof(info) || !header->addr)
return -EINVAL;
if (header->queue_id != (u16)-1) {
pr_warn("%s: queue_id is wrong %x\n",
__func__, header->queue_id);
return -EINVAL;
}
if (copy_from_user(&info, argp, sizeof(info)))
return -EFAULT;
ublk_dump_dev_info(&info);
if (header->dev_id != info.dev_id) {
pr_warn("%s: dev id not match %u %u\n",
__func__, header->dev_id, info.dev_id);
return -EINVAL;
}
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
ret = mutex_lock_killable(&ublk_ctl_mutex);
if (ret)
return ret;
ret = -ENOMEM;
ub = kzalloc(sizeof(*ub), GFP_KERNEL);
if (!ub)
goto out_unlock;
mutex_init(&ub->mutex);
spin_lock_init(&ub->mm_lock);
INIT_WORK(&ub->stop_work, ublk_stop_work_fn);
INIT_DELAYED_WORK(&ub->monitor_work, ublk_daemon_monitor_work);
ret = ublk_alloc_dev_number(ub, header->dev_id);
if (ret < 0)
goto out_free_ub;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
memcpy(&ub->dev_info, &info, sizeof(info));
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
/* update device id */
ub->dev_info.dev_id = ub->ub_number;
/*
* 64bit flags will be copied back to userspace as feature
* negotiation result, so have to clear flags which driver
* doesn't support yet, then userspace can get correct flags
* (features) to handle.
*/
ub->dev_info.flags &= UBLK_F_ALL;
/* We are not ready to support zero copy */
ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;
ub->dev_info.nr_hw_queues = min_t(unsigned int,
ub->dev_info.nr_hw_queues, nr_cpu_ids);
ublk_align_max_io_size(ub);
ret = ublk_init_queues(ub);
if (ret)
goto out_free_dev_number;
ret = ublk_add_tag_set(ub);
if (ret)
goto out_deinit_queues;
ret = -EFAULT;
if (copy_to_user(argp, &ub->dev_info, sizeof(info)))
goto out_free_tag_set;
/*
* Add the char dev so that ublksrv daemon can be setup.
* ublk_add_chdev() will cleanup everything if it fails.
*/
ret = ublk_add_chdev(ub);
goto out_unlock;
out_free_tag_set:
blk_mq_free_tag_set(&ub->tag_set);
out_deinit_queues:
ublk_deinit_queues(ub);
out_free_dev_number:
ublk_free_dev_number(ub);
out_free_ub:
mutex_destroy(&ub->mutex);
kfree(ub);
out_unlock:
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
mutex_unlock(&ublk_ctl_mutex);
return ret;
}
static inline bool ublk_idr_freed(int id)
{
void *ptr;
spin_lock(&ublk_idr_lock);
ptr = idr_find(&ublk_index_idr, id);
spin_unlock(&ublk_idr_lock);
return ptr == NULL;
}
static int ublk_ctrl_del_dev(int idx)
{
struct ublk_device *ub;
int ret;
ret = mutex_lock_killable(&ublk_ctl_mutex);
if (ret)
return ret;
ub = ublk_get_device_from_id(idx);
if (ub) {
ublk_remove(ub);
ublk_put_device(ub);
ret = 0;
} else {
ret = -ENODEV;
}
/*
* Wait until the idr is removed, then it can be reused after
* DEL_DEV command is returned.
*/
if (!ret)
wait_event(ublk_idr_wq, ublk_idr_freed(idx));
mutex_unlock(&ublk_ctl_mutex);
return ret;
}
static inline void ublk_ctrl_cmd_dump(struct io_uring_cmd *cmd)
{
struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
pr_devel("%s: cmd_op %x, dev id %d qid %d data %llx buf %llx len %u\n",
__func__, cmd->cmd_op, header->dev_id, header->queue_id,
header->data[0], header->addr, header->len);
}
static int ublk_ctrl_stop_dev(struct io_uring_cmd *cmd)
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
{
struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
struct ublk_device *ub;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
ub = ublk_get_device_from_id(header->dev_id);
if (!ub)
return -EINVAL;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
ublk_stop_dev(ub);
cancel_work_sync(&ub->stop_work);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
ublk_put_device(ub);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
return 0;
}
static int ublk_ctrl_get_dev_info(struct io_uring_cmd *cmd)
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
{
struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
void __user *argp = (void __user *)(unsigned long)header->addr;
struct ublk_device *ub;
int ret = 0;
if (header->len < sizeof(struct ublksrv_ctrl_dev_info) || !header->addr)
return -EINVAL;
ub = ublk_get_device_from_id(header->dev_id);
if (!ub)
return -EINVAL;
if (copy_to_user(argp, &ub->dev_info, sizeof(ub->dev_info)))
ret = -EFAULT;
ublk_put_device(ub);
return ret;
}
static int ublk_ctrl_get_params(struct io_uring_cmd *cmd)
{
struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
void __user *argp = (void __user *)(unsigned long)header->addr;
struct ublk_params_header ph;
struct ublk_device *ub;
int ret;
if (header->len <= sizeof(ph) || !header->addr)
return -EINVAL;
if (copy_from_user(&ph, argp, sizeof(ph)))
return -EFAULT;
if (ph.len > header->len || !ph.len)
return -EINVAL;
if (ph.len > sizeof(struct ublk_params))
ph.len = sizeof(struct ublk_params);
ub = ublk_get_device_from_id(header->dev_id);
if (!ub)
return -EINVAL;
mutex_lock(&ub->mutex);
if (copy_to_user(argp, &ub->params, ph.len))
ret = -EFAULT;
else
ret = 0;
mutex_unlock(&ub->mutex);
ublk_put_device(ub);
return ret;
}
static int ublk_ctrl_set_params(struct io_uring_cmd *cmd)
{
struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
void __user *argp = (void __user *)(unsigned long)header->addr;
struct ublk_params_header ph;
struct ublk_device *ub;
int ret = -EFAULT;
if (header->len <= sizeof(ph) || !header->addr)
return -EINVAL;
if (copy_from_user(&ph, argp, sizeof(ph)))
return -EFAULT;
if (ph.len > header->len || !ph.len || !ph.types)
return -EINVAL;
if (ph.len > sizeof(struct ublk_params))
ph.len = sizeof(struct ublk_params);
ub = ublk_get_device_from_id(header->dev_id);
if (!ub)
return -EINVAL;
/* parameters can only be changed when device isn't live */
mutex_lock(&ub->mutex);
if (ub->dev_info.state == UBLK_S_DEV_LIVE) {
ret = -EACCES;
} else if (copy_from_user(&ub->params, argp, ph.len)) {
ret = -EFAULT;
} else {
/* clear all we don't support yet */
ub->params.types &= UBLK_PARAM_TYPE_ALL;
ret = ublk_validate_params(ub);
}
mutex_unlock(&ub->mutex);
ublk_put_device(ub);
return ret;
}
static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd,
unsigned int issue_flags)
{
struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
int ret = -EINVAL;
ublk_ctrl_cmd_dump(cmd);
if (!(issue_flags & IO_URING_F_SQE128))
goto out;
ret = -EPERM;
if (!capable(CAP_SYS_ADMIN))
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
goto out;
ret = -ENODEV;
switch (cmd->cmd_op) {
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
case UBLK_CMD_START_DEV:
ret = ublk_ctrl_start_dev(cmd);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
break;
case UBLK_CMD_STOP_DEV:
ret = ublk_ctrl_stop_dev(cmd);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
break;
case UBLK_CMD_GET_DEV_INFO:
ret = ublk_ctrl_get_dev_info(cmd);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
break;
case UBLK_CMD_ADD_DEV:
ret = ublk_ctrl_add_dev(cmd);
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
break;
case UBLK_CMD_DEL_DEV:
ret = ublk_ctrl_del_dev(header->dev_id);
break;
case UBLK_CMD_GET_QUEUE_AFFINITY:
ret = ublk_ctrl_get_queue_affinity(cmd);
break;
case UBLK_CMD_GET_PARAMS:
ret = ublk_ctrl_get_params(cmd);
break;
case UBLK_CMD_SET_PARAMS:
ret = ublk_ctrl_set_params(cmd);
break;
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
default:
break;
}
ublk_drv: add io_uring based userspace block driver This is the driver part of userspace block driver(ublk driver), the other part is userspace daemon part(ublksrv)[1]. The two parts communicate by io_uring's IORING_OP_URING_CMD with one shared cmd buffer for storing io command, and the buffer is read only for ublksrv, each io command is indexed by io request tag directly, and is written by ublk driver. For example, when one READ io request is submitted to ublk block driver, ublk driver stores the io command into cmd buffer first, then completes one IORING_OP_URING_CMD for notifying ublksrv, and the URING_CMD is issued to ublk driver beforehand by ublksrv for getting notification of any new io request, and each URING_CMD is associated with one io request by tag. After ublksrv gets the io command, it translates and handles the ublk io request, such as, for the ublk-loop target, ublksrv translates the request into same request on another file or disk, like the kernel loop block driver. In ublksrv's implementation, the io is still handled by io_uring, and share same ring with IORING_OP_URING_CMD command. When the target io request is done, the same IORING_OP_URING_CMD is issued to ublk driver for both committing io request result and getting future notification of new io request. Another thing done by ublk driver is to copy data between kernel io request and ublksrv's io buffer: 1) before ubsrv handles WRITE request, copy the request's data into ublksrv's userspace io buffer, so that ublksrv can handle the write request 2) after ubsrv handles READ request, copy ublksrv's userspace io buffer into this READ request, then ublk driver can complete the READ request Zero copy may be switched if mm is ready to support it. ublk driver doesn't handle any logic of the specific user space driver, so it is small/simple enough. [1] ublksrv https://github.com/ming1/ubdsrv Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220713140711.97356-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-13 22:07:10 +08:00
out:
io_uring_cmd_done(cmd, ret, 0);
pr_devel("%s: cmd done ret %d cmd_op %x, dev id %d qid %d\n",
__func__, ret, cmd->cmd_op, header->dev_id, header->queue_id);
return -EIOCBQUEUED;
}
static const struct file_operations ublk_ctl_fops = {
.open = nonseekable_open,
.uring_cmd = ublk_ctrl_uring_cmd,
.owner = THIS_MODULE,
.llseek = noop_llseek,
};
static struct miscdevice ublk_misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = "ublk-control",
.fops = &ublk_ctl_fops,
};
static int __init ublk_init(void)
{
int ret;
init_waitqueue_head(&ublk_idr_wq);
ret = misc_register(&ublk_misc);
if (ret)
return ret;
ret = alloc_chrdev_region(&ublk_chr_devt, 0, UBLK_MINORS, "ublk-char");
if (ret)
goto unregister_mis;
ublk_chr_class = class_create(THIS_MODULE, "ublk-char");
if (IS_ERR(ublk_chr_class)) {
ret = PTR_ERR(ublk_chr_class);
goto free_chrdev_region;
}
return 0;
free_chrdev_region:
unregister_chrdev_region(ublk_chr_devt, UBLK_MINORS);
unregister_mis:
misc_deregister(&ublk_misc);
return ret;
}
static void __exit ublk_exit(void)
{
struct ublk_device *ub;
int id;
class_destroy(ublk_chr_class);
misc_deregister(&ublk_misc);
idr_for_each_entry(&ublk_index_idr, ub, id)
ublk_remove(ub);
idr_destroy(&ublk_index_idr);
unregister_chrdev_region(ublk_chr_devt, UBLK_MINORS);
}
module_init(ublk_init);
module_exit(ublk_exit);
MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
MODULE_LICENSE("GPL");