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OpenCloudOS-Kernel/block/genhd.c

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// SPDX-License-Identifier: GPL-2.0
/*
* gendisk handling
*
* Portions Copyright (C) 2020 Christoph Hellwig
*/
#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/fs.h>
#include <linux/kdev_t.h>
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/kmod.h>
#include <linux/major.h>
#include <linux/mutex.h>
#include <linux/idr.h>
#include <linux/log2.h>
#include <linux/pm_runtime.h>
#include <linux/badblocks.h>
#include <linux/part_stat.h>
#include <linux/blktrace_api.h>
#include "blk-throttle.h"
#include "blk.h"
#include "blk-mq-sched.h"
#include "blk-rq-qos.h"
#include "blk-cgroup.h"
static struct kobject *block_depr;
/*
* Unique, monotonically increasing sequential number associated with block
* devices instances (i.e. incremented each time a device is attached).
* Associating uevents with block devices in userspace is difficult and racy:
* the uevent netlink socket is lossy, and on slow and overloaded systems has
* a very high latency.
* Block devices do not have exclusive owners in userspace, any process can set
* one up (e.g. loop devices). Moreover, device names can be reused (e.g. loop0
* can be reused again and again).
* A userspace process setting up a block device and watching for its events
* cannot thus reliably tell whether an event relates to the device it just set
* up or another earlier instance with the same name.
* This sequential number allows userspace processes to solve this problem, and
* uniquely associate an uevent to the lifetime to a device.
*/
static atomic64_t diskseq;
/* for extended dynamic devt allocation, currently only one major is used */
#define NR_EXT_DEVT (1 << MINORBITS)
static DEFINE_IDA(ext_devt_ida);
void set_capacity(struct gendisk *disk, sector_t sectors)
{
bdev_set_nr_sectors(disk->part0, sectors);
}
EXPORT_SYMBOL(set_capacity);
/*
* Set disk capacity and notify if the size is not currently zero and will not
* be set to zero. Returns true if a uevent was sent, otherwise false.
*/
bool set_capacity_and_notify(struct gendisk *disk, sector_t size)
{
sector_t capacity = get_capacity(disk);
char *envp[] = { "RESIZE=1", NULL };
set_capacity(disk, size);
/*
* Only print a message and send a uevent if the gendisk is user visible
* and alive. This avoids spamming the log and udev when setting the
* initial capacity during probing.
*/
if (size == capacity ||
!disk_live(disk) ||
(disk->flags & GENHD_FL_HIDDEN))
return false;
pr_info("%s: detected capacity change from %lld to %lld\n",
disk->disk_name, capacity, size);
/*
* Historically we did not send a uevent for changes to/from an empty
* device.
*/
if (!capacity || !size)
return false;
kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
return true;
}
EXPORT_SYMBOL_GPL(set_capacity_and_notify);
static void part_stat_read_all(struct block_device *part,
struct disk_stats *stat)
{
int cpu;
memset(stat, 0, sizeof(struct disk_stats));
for_each_possible_cpu(cpu) {
struct disk_stats *ptr = per_cpu_ptr(part->bd_stats, cpu);
int group;
for (group = 0; group < NR_STAT_GROUPS; group++) {
stat->nsecs[group] += ptr->nsecs[group];
stat->sectors[group] += ptr->sectors[group];
stat->ios[group] += ptr->ios[group];
stat->merges[group] += ptr->merges[group];
}
stat->io_ticks += ptr->io_ticks;
}
}
unsigned int part_in_flight(struct block_device *part)
{
unsigned int inflight = 0;
int cpu;
for_each_possible_cpu(cpu) {
inflight += part_stat_local_read_cpu(part, in_flight[0], cpu) +
part_stat_local_read_cpu(part, in_flight[1], cpu);
}
if ((int)inflight < 0)
inflight = 0;
return inflight;
}
static void part_in_flight_rw(struct block_device *part,
unsigned int inflight[2])
{
int cpu;
inflight[0] = 0;
inflight[1] = 0;
for_each_possible_cpu(cpu) {
inflight[0] += part_stat_local_read_cpu(part, in_flight[0], cpu);
inflight[1] += part_stat_local_read_cpu(part, in_flight[1], cpu);
}
if ((int)inflight[0] < 0)
inflight[0] = 0;
if ((int)inflight[1] < 0)
inflight[1] = 0;
}
/*
* Can be deleted altogether. Later.
*
*/
#define BLKDEV_MAJOR_HASH_SIZE 255
static struct blk_major_name {
struct blk_major_name *next;
int major;
char name[16];
#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
void (*probe)(dev_t devt);
#endif
} *major_names[BLKDEV_MAJOR_HASH_SIZE];
static DEFINE_MUTEX(major_names_lock);
static DEFINE_SPINLOCK(major_names_spinlock);
/* index in the above - for now: assume no multimajor ranges */
static inline int major_to_index(unsigned major)
{
return major % BLKDEV_MAJOR_HASH_SIZE;
}
#ifdef CONFIG_PROC_FS
void blkdev_show(struct seq_file *seqf, off_t offset)
{
struct blk_major_name *dp;
spin_lock(&major_names_spinlock);
for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next)
if (dp->major == offset)
seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
spin_unlock(&major_names_spinlock);
}
#endif /* CONFIG_PROC_FS */
/**
* __register_blkdev - register a new block device
*
* @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If
* @major = 0, try to allocate any unused major number.
* @name: the name of the new block device as a zero terminated string
* @probe: pre-devtmpfs / pre-udev callback used to create disks when their
* pre-created device node is accessed. When a probe call uses
* add_disk() and it fails the driver must cleanup resources. This
* interface may soon be removed.
*
* The @name must be unique within the system.
*
* The return value depends on the @major input parameter:
*
* - if a major device number was requested in range [1..BLKDEV_MAJOR_MAX-1]
* then the function returns zero on success, or a negative error code
* - if any unused major number was requested with @major = 0 parameter
* then the return value is the allocated major number in range
* [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise
*
* See Documentation/admin-guide/devices.txt for the list of allocated
* major numbers.
*
* Use register_blkdev instead for any new code.
*/
int __register_blkdev(unsigned int major, const char *name,
void (*probe)(dev_t devt))
{
struct blk_major_name **n, *p;
int index, ret = 0;
mutex_lock(&major_names_lock);
/* temporary */
if (major == 0) {
for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
if (major_names[index] == NULL)
break;
}
if (index == 0) {
printk("%s: failed to get major for %s\n",
__func__, name);
ret = -EBUSY;
goto out;
}
major = index;
ret = major;
}
if (major >= BLKDEV_MAJOR_MAX) {
pr_err("%s: major requested (%u) is greater than the maximum (%u) for %s\n",
__func__, major, BLKDEV_MAJOR_MAX-1, name);
ret = -EINVAL;
goto out;
}
p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
if (p == NULL) {
ret = -ENOMEM;
goto out;
}
p->major = major;
#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
p->probe = probe;
#endif
strscpy(p->name, name, sizeof(p->name));
p->next = NULL;
index = major_to_index(major);
spin_lock(&major_names_spinlock);
for (n = &major_names[index]; *n; n = &(*n)->next) {
if ((*n)->major == major)
break;
}
if (!*n)
*n = p;
else
ret = -EBUSY;
spin_unlock(&major_names_spinlock);
if (ret < 0) {
printk("register_blkdev: cannot get major %u for %s\n",
major, name);
kfree(p);
}
out:
mutex_unlock(&major_names_lock);
return ret;
}
EXPORT_SYMBOL(__register_blkdev);
void unregister_blkdev(unsigned int major, const char *name)
{
struct blk_major_name **n;
struct blk_major_name *p = NULL;
int index = major_to_index(major);
mutex_lock(&major_names_lock);
spin_lock(&major_names_spinlock);
for (n = &major_names[index]; *n; n = &(*n)->next)
if ((*n)->major == major)
break;
if (!*n || strcmp((*n)->name, name)) {
WARN_ON(1);
} else {
p = *n;
*n = p->next;
}
spin_unlock(&major_names_spinlock);
mutex_unlock(&major_names_lock);
kfree(p);
}
EXPORT_SYMBOL(unregister_blkdev);
int blk_alloc_ext_minor(void)
{
int idx;
idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT - 1, GFP_KERNEL);
if (idx == -ENOSPC)
return -EBUSY;
return idx;
}
void blk_free_ext_minor(unsigned int minor)
{
ida_free(&ext_devt_ida, minor);
}
void disk_uevent(struct gendisk *disk, enum kobject_action action)
{
struct block_device *part;
unsigned long idx;
rcu_read_lock();
xa_for_each(&disk->part_tbl, idx, part) {
if (bdev_is_partition(part) && !bdev_nr_sectors(part))
continue;
if (!kobject_get_unless_zero(&part->bd_device.kobj))
continue;
rcu_read_unlock();
kobject_uevent(bdev_kobj(part), action);
put_device(&part->bd_device);
rcu_read_lock();
}
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(disk_uevent);
int disk_scan_partitions(struct gendisk *disk, blk_mode_t mode)
{
struct block_device *bdev;
int ret = 0;
if (!disk_has_partscan(disk))
return -EINVAL;
if (disk->open_partitions)
return -EBUSY;
/*
* If the device is opened exclusively by current thread already, it's
* safe to scan partitons, otherwise, use bd_prepare_to_claim() to
* synchronize with other exclusive openers and other partition
* scanners.
*/
if (!(mode & BLK_OPEN_EXCL)) {
ret = bd_prepare_to_claim(disk->part0, disk_scan_partitions,
NULL);
if (ret)
return ret;
}
set_bit(GD_NEED_PART_SCAN, &disk->state);
bdev = blkdev_get_by_dev(disk_devt(disk), mode & ~BLK_OPEN_EXCL, NULL,
NULL);
if (IS_ERR(bdev))
ret = PTR_ERR(bdev);
else
blkdev_put(bdev, NULL);
/*
* If blkdev_get_by_dev() failed early, GD_NEED_PART_SCAN is still set,
* and this will cause that re-assemble partitioned raid device will
* creat partition for underlying disk.
*/
clear_bit(GD_NEED_PART_SCAN, &disk->state);
if (!(mode & BLK_OPEN_EXCL))
bd_abort_claiming(disk->part0, disk_scan_partitions);
return ret;
}
/**
* device_add_disk - add disk information to kernel list
* @parent: parent device for the disk
* @disk: per-device partitioning information
* @groups: Additional per-device sysfs groups
*
* This function registers the partitioning information in @disk
* with the kernel.
*/
int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
const struct attribute_group **groups)
{
struct device *ddev = disk_to_dev(disk);
int ret;
/* Only makes sense for bio-based to set ->poll_bio */
if (queue_is_mq(disk->queue) && disk->fops->poll_bio)
return -EINVAL;
/*
* The disk queue should now be all set with enough information about
* the device for the elevator code to pick an adequate default
* elevator if one is needed, that is, for devices requesting queue
* registration.
*/
elevator_init_mq(disk->queue);
/* Mark bdev as having a submit_bio, if needed */
disk->part0->bd_has_submit_bio = disk->fops->submit_bio != NULL;
/*
* If the driver provides an explicit major number it also must provide
* the number of minors numbers supported, and those will be used to
* setup the gendisk.
* Otherwise just allocate the device numbers for both the whole device
* and all partitions from the extended dev_t space.
*/
ret = -EINVAL;
if (disk->major) {
if (WARN_ON(!disk->minors))
goto out_exit_elevator;
if (disk->minors > DISK_MAX_PARTS) {
pr_err("block: can't allocate more than %d partitions\n",
DISK_MAX_PARTS);
disk->minors = DISK_MAX_PARTS;
}
if (disk->first_minor > MINORMASK ||
disk->minors > MINORMASK + 1 ||
disk->first_minor + disk->minors > MINORMASK + 1)
goto out_exit_elevator;
} else {
if (WARN_ON(disk->minors))
goto out_exit_elevator;
ret = blk_alloc_ext_minor();
if (ret < 0)
goto out_exit_elevator;
disk->major = BLOCK_EXT_MAJOR;
disk->first_minor = ret;
}
/* delay uevents, until we scanned partition table */
dev_set_uevent_suppress(ddev, 1);
ddev->parent = parent;
ddev->groups = groups;
dev_set_name(ddev, "%s", disk->disk_name);
if (!(disk->flags & GENHD_FL_HIDDEN))
ddev->devt = MKDEV(disk->major, disk->first_minor);
ret = device_add(ddev);
if (ret)
goto out_free_ext_minor;
ret = disk_alloc_events(disk);
if (ret)
goto out_device_del;
ret = sysfs_create_link(block_depr, &ddev->kobj,
kobject_name(&ddev->kobj));
if (ret)
goto out_device_del;
/*
* avoid probable deadlock caused by allocating memory with
* GFP_KERNEL in runtime_resume callback of its all ancestor
* devices
*/
pm_runtime_set_memalloc_noio(ddev, true);
disk->part0->bd_holder_dir =
kobject_create_and_add("holders", &ddev->kobj);
if (!disk->part0->bd_holder_dir) {
ret = -ENOMEM;
goto out_del_block_link;
}
disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
if (!disk->slave_dir) {
ret = -ENOMEM;
goto out_put_holder_dir;
}
ret = blk_register_queue(disk);
if (ret)
goto out_put_slave_dir;
if (!(disk->flags & GENHD_FL_HIDDEN)) {
ret = bdi_register(disk->bdi, "%u:%u",
disk->major, disk->first_minor);
if (ret)
goto out_unregister_queue;
bdi_set_owner(disk->bdi, ddev);
ret = sysfs_create_link(&ddev->kobj,
&disk->bdi->dev->kobj, "bdi");
if (ret)
goto out_unregister_bdi;
/* Make sure the first partition scan will be proceed */
if (get_capacity(disk) && disk_has_partscan(disk))
set_bit(GD_NEED_PART_SCAN, &disk->state);
bdev_add(disk->part0, ddev->devt);
if (get_capacity(disk))
disk_scan_partitions(disk, BLK_OPEN_READ);
/*
* Announce the disk and partitions after all partitions are
* created. (for hidden disks uevents remain suppressed forever)
*/
dev_set_uevent_suppress(ddev, 0);
disk_uevent(disk, KOBJ_ADD);
} else {
/*
* Even if the block_device for a hidden gendisk is not
* registered, it needs to have a valid bd_dev so that the
* freeing of the dynamic major works.
*/
disk->part0->bd_dev = MKDEV(disk->major, disk->first_minor);
}
disk_update_readahead(disk);
disk_add_events(disk);
set_bit(GD_ADDED, &disk->state);
return 0;
out_unregister_bdi:
if (!(disk->flags & GENHD_FL_HIDDEN))
bdi_unregister(disk->bdi);
out_unregister_queue:
blk_unregister_queue(disk);
rq_qos_exit(disk->queue);
out_put_slave_dir:
kobject_put(disk->slave_dir);
disk->slave_dir = NULL;
out_put_holder_dir:
kobject_put(disk->part0->bd_holder_dir);
out_del_block_link:
sysfs_remove_link(block_depr, dev_name(ddev));
pm_runtime_set_memalloc_noio(ddev, false);
out_device_del:
device_del(ddev);
out_free_ext_minor:
if (disk->major == BLOCK_EXT_MAJOR)
blk_free_ext_minor(disk->first_minor);
out_exit_elevator:
if (disk->queue->elevator)
elevator_exit(disk->queue);
return ret;
}
EXPORT_SYMBOL(device_add_disk);
static void blk_report_disk_dead(struct gendisk *disk, bool surprise)
{
struct block_device *bdev;
unsigned long idx;
rcu_read_lock();
xa_for_each(&disk->part_tbl, idx, bdev) {
if (!kobject_get_unless_zero(&bdev->bd_device.kobj))
continue;
rcu_read_unlock();
bdev_mark_dead(bdev, surprise);
put_device(&bdev->bd_device);
rcu_read_lock();
}
rcu_read_unlock();
}
static void __blk_mark_disk_dead(struct gendisk *disk)
{
/*
* Fail any new I/O.
*/
if (test_and_set_bit(GD_DEAD, &disk->state))
return;
if (test_bit(GD_OWNS_QUEUE, &disk->state))
blk_queue_flag_set(QUEUE_FLAG_DYING, disk->queue);
/*
* Stop buffered writers from dirtying pages that can't be written out.
*/
set_capacity(disk, 0);
/*
* Prevent new I/O from crossing bio_queue_enter().
*/
blk_queue_start_drain(disk->queue);
}
/**
* blk_mark_disk_dead - mark a disk as dead
* @disk: disk to mark as dead
*
* Mark as disk as dead (e.g. surprise removed) and don't accept any new I/O
* to this disk.
*/
void blk_mark_disk_dead(struct gendisk *disk)
{
__blk_mark_disk_dead(disk);
blk_report_disk_dead(disk, true);
}
EXPORT_SYMBOL_GPL(blk_mark_disk_dead);
/**
* del_gendisk - remove the gendisk
* @disk: the struct gendisk to remove
*
* Removes the gendisk and all its associated resources. This deletes the
* partitions associated with the gendisk, and unregisters the associated
* request_queue.
*
* This is the counter to the respective __device_add_disk() call.
*
* The final removal of the struct gendisk happens when its refcount reaches 0
* with put_disk(), which should be called after del_gendisk(), if
* __device_add_disk() was used.
*
* Drivers exist which depend on the release of the gendisk to be synchronous,
* it should not be deferred.
*
* Context: can sleep
*/
void del_gendisk(struct gendisk *disk)
{
struct request_queue *q = disk->queue;
struct block_device *part;
unsigned long idx;
might_sleep();
if (WARN_ON_ONCE(!disk_live(disk) && !(disk->flags & GENHD_FL_HIDDEN)))
return;
disk_del_events(disk);
/*
* Prevent new openers by unlinked the bdev inode.
*/
mutex_lock(&disk->open_mutex);
xa_for_each(&disk->part_tbl, idx, part)
remove_inode_hash(part->bd_inode);
mutex_unlock(&disk->open_mutex);
/*
* Tell the file system to write back all dirty data and shut down if
* it hasn't been notified earlier.
*/
if (!test_bit(GD_DEAD, &disk->state))
blk_report_disk_dead(disk, false);
/*
* Drop all partitions now that the disk is marked dead.
*/
mutex_lock(&disk->open_mutex);
__blk_mark_disk_dead(disk);
xa_for_each_start(&disk->part_tbl, idx, part, 1)
drop_partition(part);
mutex_unlock(&disk->open_mutex);
if (!(disk->flags & GENHD_FL_HIDDEN)) {
sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
/*
* Unregister bdi before releasing device numbers (as they can
* get reused and we'd get clashes in sysfs).
*/
bdi_unregister(disk->bdi);
}
blk_unregister_queue(disk);
kobject_put(disk->part0->bd_holder_dir);
kobject_put(disk->slave_dir);
disk->slave_dir = NULL;
part_stat_set_all(disk->part0, 0);
disk->part0->bd_stamp = 0;
sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
device_del(disk_to_dev(disk));
blk_mq_freeze_queue_wait(q);
blk_throtl_cancel_bios(disk);
blk_sync_queue(q);
blk_flush_integrity();
if (queue_is_mq(q))
blk_mq_cancel_work_sync(q);
blk_mq_quiesce_queue(q);
if (q->elevator) {
mutex_lock(&q->sysfs_lock);
elevator_exit(q);
mutex_unlock(&q->sysfs_lock);
}
rq_qos_exit(q);
blk_mq_unquiesce_queue(q);
/*
* If the disk does not own the queue, allow using passthrough requests
* again. Else leave the queue frozen to fail all I/O.
*/
if (!test_bit(GD_OWNS_QUEUE, &disk->state)) {
blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);
__blk_mq_unfreeze_queue(q, true);
} else {
if (queue_is_mq(q))
blk_mq_exit_queue(q);
}
}
EXPORT_SYMBOL(del_gendisk);
/**
* invalidate_disk - invalidate the disk
* @disk: the struct gendisk to invalidate
*
* A helper to invalidates the disk. It will clean the disk's associated
* buffer/page caches and reset its internal states so that the disk
* can be reused by the drivers.
*
* Context: can sleep
*/
void invalidate_disk(struct gendisk *disk)
{
struct block_device *bdev = disk->part0;
invalidate_bdev(bdev);
bdev->bd_inode->i_mapping->wb_err = 0;
set_capacity(disk, 0);
}
EXPORT_SYMBOL(invalidate_disk);
static int hide_disk(struct gendisk *gd)
{
struct device *ddev = disk_to_dev(gd);
struct block_device *part;
int ret;
unsigned long idx;
ret = device_hide(ddev);
if (ret)
return ret;
rcu_read_lock();
xa_for_each(&gd->part_tbl, idx, part) {
if (bdev_is_partition(part) && !bdev_nr_sectors(part))
continue;
if (!kobject_get_unless_zero(&part->bd_device.kobj))
continue;
rcu_read_unlock();
device_hide(&part->bd_device);
put_device(&part->bd_device);
rcu_read_lock();
}
rcu_read_unlock();
sysfs_remove_link(block_depr, dev_name(ddev));
return ret;
}
static int unhide_disk(struct gendisk *gd)
{
struct device *ddev = disk_to_dev(gd);
struct block_device *part;
int ret;
unsigned long idx;
ret = device_unhide(ddev);
if (ret)
return ret;
rcu_read_lock();
xa_for_each(&gd->part_tbl, idx, part) {
if (bdev_is_partition(part) && !bdev_nr_sectors(part))
continue;
if (!kobject_get_unless_zero(&part->bd_device.kobj))
continue;
rcu_read_unlock();
device_unhide(&part->bd_device);
put_device(&part->bd_device);
rcu_read_lock();
}
rcu_read_unlock();
if (sysfs_create_link(block_depr, &ddev->kobj,
kobject_name(&ddev->kobj)))
pr_warn("%s: failed to restore /sys/block link\n",
gd->disk_name);
return ret;
}
/* sysfs access to bad-blocks list. */
static ssize_t disk_badblocks_show(struct device *dev,
struct device_attribute *attr,
char *page)
{
struct gendisk *disk = dev_to_disk(dev);
if (!disk->bb)
return sprintf(page, "\n");
return badblocks_show(disk->bb, page, 0);
}
static ssize_t disk_badblocks_store(struct device *dev,
struct device_attribute *attr,
const char *page, size_t len)
{
struct gendisk *disk = dev_to_disk(dev);
if (!disk->bb)
return -ENXIO;
return badblocks_store(disk->bb, page, len, 0);
}
#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
void blk_request_module(dev_t devt)
{
unsigned int major = MAJOR(devt);
struct blk_major_name **n;
mutex_lock(&major_names_lock);
for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) {
if ((*n)->major == major && (*n)->probe) {
(*n)->probe(devt);
mutex_unlock(&major_names_lock);
return;
}
}
mutex_unlock(&major_names_lock);
if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
/* Make old-style 2.4 aliases work */
request_module("block-major-%d", MAJOR(devt));
}
#endif /* CONFIG_BLOCK_LEGACY_AUTOLOAD */
#ifdef CONFIG_PROC_FS
/* iterator */
static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
{
loff_t skip = *pos;
struct class_dev_iter *iter;
struct device *dev;
iter = kmalloc(sizeof(*iter), GFP_KERNEL);
if (!iter)
return ERR_PTR(-ENOMEM);
seqf->private = iter;
class_dev_iter_init(iter, &block_class, NULL, &disk_type);
do {
dev = class_dev_iter_next(iter);
if (!dev)
return NULL;
} while (skip--);
return dev_to_disk(dev);
}
static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
{
struct device *dev;
(*pos)++;
dev = class_dev_iter_next(seqf->private);
if (dev)
return dev_to_disk(dev);
return NULL;
}
static void disk_seqf_stop(struct seq_file *seqf, void *v)
{
struct class_dev_iter *iter = seqf->private;
/* stop is called even after start failed :-( */
if (iter) {
class_dev_iter_exit(iter);
kfree(iter);
seqf->private = NULL;
}
}
static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
{
void *p;
p = disk_seqf_start(seqf, pos);
if (!IS_ERR_OR_NULL(p) && !*pos)
seq_puts(seqf, "major minor #blocks name\n\n");
return p;
}
static int show_partition(struct seq_file *seqf, void *v)
{
struct gendisk *sgp = v;
struct block_device *part;
unsigned long idx;
if (!get_capacity(sgp) || (sgp->flags & GENHD_FL_HIDDEN))
return 0;
rcu_read_lock();
xa_for_each(&sgp->part_tbl, idx, part) {
if (!bdev_nr_sectors(part))
continue;
seq_printf(seqf, "%4d %7d %10llu %pg\n",
MAJOR(part->bd_dev), MINOR(part->bd_dev),
bdev_nr_sectors(part) >> 1, part);
}
rcu_read_unlock();
return 0;
}
static const struct seq_operations partitions_op = {
.start = show_partition_start,
.next = disk_seqf_next,
.stop = disk_seqf_stop,
.show = show_partition
};
#endif
static int __init genhd_device_init(void)
{
int error;
error = class_register(&block_class);
if (unlikely(error))
return error;
blk_dev_init();
register_blkdev(BLOCK_EXT_MAJOR, "blkext");
/* create top-level block dir */
block_depr = kobject_create_and_add("block", NULL);
return 0;
}
subsys_initcall(genhd_device_init);
static ssize_t disk_range_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%d\n", disk->minors);
}
static ssize_t disk_ext_range_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%d\n",
(disk->flags & GENHD_FL_NO_PART) ? 1 : DISK_MAX_PARTS);
}
static ssize_t disk_removable_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%d\n",
(disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
}
static ssize_t disk_hidden_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%d\n",
(disk->flags & GENHD_FL_HIDDEN ? 1 : 0));
}
static ssize_t disk_ro_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0);
}
ssize_t part_size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%llu\n", bdev_nr_sectors(dev_to_bdev(dev)));
}
ssize_t part_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct block_device *bdev = dev_to_bdev(dev);
struct request_queue *q = bdev_get_queue(bdev);
struct disk_stats stat;
unsigned int inflight;
if (queue_is_mq(q))
inflight = blk_mq_in_flight(q, bdev);
else
inflight = part_in_flight(bdev);
if (inflight) {
part_stat_lock();
update_io_ticks(bdev, jiffies, true);
part_stat_unlock();
}
part_stat_read_all(bdev, &stat);
return sprintf(buf,
"%8lu %8lu %8llu %8u "
"%8lu %8lu %8llu %8u "
"%8u %8u %8u "
"%8lu %8lu %8llu %8u "
"%8lu %8u"
"\n",
stat.ios[STAT_READ],
stat.merges[STAT_READ],
(unsigned long long)stat.sectors[STAT_READ],
(unsigned int)div_u64(stat.nsecs[STAT_READ], NSEC_PER_MSEC),
stat.ios[STAT_WRITE],
stat.merges[STAT_WRITE],
(unsigned long long)stat.sectors[STAT_WRITE],
(unsigned int)div_u64(stat.nsecs[STAT_WRITE], NSEC_PER_MSEC),
inflight,
jiffies_to_msecs(stat.io_ticks),
(unsigned int)div_u64(stat.nsecs[STAT_READ] +
stat.nsecs[STAT_WRITE] +
stat.nsecs[STAT_DISCARD] +
stat.nsecs[STAT_FLUSH],
NSEC_PER_MSEC),
stat.ios[STAT_DISCARD],
stat.merges[STAT_DISCARD],
(unsigned long long)stat.sectors[STAT_DISCARD],
(unsigned int)div_u64(stat.nsecs[STAT_DISCARD], NSEC_PER_MSEC),
stat.ios[STAT_FLUSH],
(unsigned int)div_u64(stat.nsecs[STAT_FLUSH], NSEC_PER_MSEC));
}
ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct block_device *bdev = dev_to_bdev(dev);
struct request_queue *q = bdev_get_queue(bdev);
unsigned int inflight[2];
if (queue_is_mq(q))
blk_mq_in_flight_rw(q, bdev, inflight);
else
part_in_flight_rw(bdev, inflight);
return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]);
}
static ssize_t disk_capability_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
dev_warn_once(dev, "the capability attribute has been deprecated.\n");
return sprintf(buf, "0\n");
}
static ssize_t disk_alignment_offset_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%d\n", bdev_alignment_offset(disk->part0));
}
static ssize_t disk_discard_alignment_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%d\n", bdev_alignment_offset(disk->part0));
}
static ssize_t diskseq_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%llu\n", disk->diskseq);
}
static ssize_t disk_hiddens_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "%d\n", device_is_hidden(dev));
}
static ssize_t disk_hiddens_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct gendisk *disk = dev_to_disk(dev);
bool hide;
int ret;
ret = kstrtobool(buf, &hide);
if (ret)
return ret;
if (hide != device_is_hidden(dev))
ret = hide ? hide_disk(disk) : unhide_disk(disk);
return ret ?: len;
}
static ssize_t partscan_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%u\n", disk_has_partscan(dev_to_disk(dev)));
}
static DEVICE_ATTR(range, 0444, disk_range_show, NULL);
static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL);
static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL);
static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL);
static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL);
static DEVICE_ATTR(size, 0444, part_size_show, NULL);
static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL);
static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL);
static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL);
static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);
static DEVICE_ATTR(diskseq, 0444, diskseq_show, NULL);
static DEVICE_ATTR(hiddens, S_IRUGO | S_IWUSR, disk_hiddens_show,
disk_hiddens_store);
static DEVICE_ATTR(partscan, 0444, partscan_show, NULL);
#ifdef CONFIG_FAIL_MAKE_REQUEST
ssize_t part_fail_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_make_it_fail);
}
ssize_t part_fail_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
int i;
if (count > 0 && sscanf(buf, "%d", &i) > 0)
dev_to_bdev(dev)->bd_make_it_fail = i;
return count;
}
static struct device_attribute dev_attr_fail =
__ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
#endif /* CONFIG_FAIL_MAKE_REQUEST */
#ifdef CONFIG_FAIL_IO_TIMEOUT
static struct device_attribute dev_attr_fail_timeout =
__ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store);
#endif
static struct attribute *disk_attrs[] = {
&dev_attr_range.attr,
&dev_attr_ext_range.attr,
&dev_attr_removable.attr,
&dev_attr_hidden.attr,
&dev_attr_ro.attr,
&dev_attr_size.attr,
&dev_attr_alignment_offset.attr,
&dev_attr_discard_alignment.attr,
&dev_attr_capability.attr,
&dev_attr_stat.attr,
&dev_attr_inflight.attr,
&dev_attr_badblocks.attr,
&dev_attr_events.attr,
&dev_attr_events_async.attr,
&dev_attr_events_poll_msecs.attr,
&dev_attr_diskseq.attr,
&dev_attr_partscan.attr,
#ifdef CONFIG_FAIL_MAKE_REQUEST
&dev_attr_fail.attr,
#endif
#ifdef CONFIG_FAIL_IO_TIMEOUT
&dev_attr_fail_timeout.attr,
#endif
&dev_attr_hiddens.attr,
NULL
};
static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n)
{
struct device *dev = container_of(kobj, typeof(*dev), kobj);
struct gendisk *disk = dev_to_disk(dev);
if (a == &dev_attr_badblocks.attr && !disk->bb)
return 0;
return a->mode;
}
static struct attribute_group disk_attr_group = {
.attrs = disk_attrs,
.is_visible = disk_visible,
};
static const struct attribute_group *disk_attr_groups[] = {
&disk_attr_group,
#ifdef CONFIG_BLK_DEV_IO_TRACE
&blk_trace_attr_group,
#endif
#ifdef CONFIG_BLK_DEV_INTEGRITY
&blk_integrity_attr_group,
#endif
NULL
};
/**
* disk_release - releases all allocated resources of the gendisk
* @dev: the device representing this disk
*
* This function releases all allocated resources of the gendisk.
*
* Drivers which used __device_add_disk() have a gendisk with a request_queue
* assigned. Since the request_queue sits on top of the gendisk for these
* drivers we also call blk_put_queue() for them, and we expect the
* request_queue refcount to reach 0 at this point, and so the request_queue
* will also be freed prior to the disk.
*
* Context: can sleep
*/
static void disk_release(struct device *dev)
{
struct gendisk *disk = dev_to_disk(dev);
might_sleep();
WARN_ON_ONCE(disk_live(disk));
blk_trace_remove(disk->queue);
/*
* To undo the all initialization from blk_mq_init_allocated_queue in
* case of a probe failure where add_disk is never called we have to
* call blk_mq_exit_queue here. We can't do this for the more common
* teardown case (yet) as the tagset can be gone by the time the disk
* is released once it was added.
*/
if (queue_is_mq(disk->queue) &&
test_bit(GD_OWNS_QUEUE, &disk->state) &&
!test_bit(GD_ADDED, &disk->state))
blk_mq_exit_queue(disk->queue);
blkcg_exit_disk(disk);
bioset_exit(&disk->bio_split);
disk_release_events(disk);
kfree(disk->random);
disk_free_zone_bitmaps(disk);
xa_destroy(&disk->part_tbl);
disk->queue->disk = NULL;
blk_put_queue(disk->queue);
if (test_bit(GD_ADDED, &disk->state) && disk->fops->free_disk)
disk->fops->free_disk(disk);
iput(disk->part0->bd_inode); /* frees the disk */
}
static int block_uevent(const struct device *dev, struct kobj_uevent_env *env)
{
const struct gendisk *disk = dev_to_disk(dev);
return add_uevent_var(env, "DISKSEQ=%llu", disk->diskseq);
}
struct class block_class = {
.name = "block",
.dev_uevent = block_uevent,
};
static char *block_devnode(const struct device *dev, umode_t *mode,
kuid_t *uid, kgid_t *gid)
{
struct gendisk *disk = dev_to_disk(dev);
if (disk->fops->devnode)
return disk->fops->devnode(disk, mode);
return NULL;
}
const struct device_type disk_type = {
.name = "disk",
.groups = disk_attr_groups,
.release = disk_release,
.devnode = block_devnode,
};
#ifdef CONFIG_PROC_FS
/*
* aggregate disk stat collector. Uses the same stats that the sysfs
* entries do, above, but makes them available through one seq_file.
*
* The output looks suspiciously like /proc/partitions with a bunch of
* extra fields.
*/
static int diskstats_show(struct seq_file *seqf, void *v)
{
struct gendisk *gp = v;
struct block_device *hd;
unsigned int inflight;
struct disk_stats stat;
unsigned long idx;
/*
if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)
seq_puts(seqf, "major minor name"
" rio rmerge rsect ruse wio wmerge "
"wsect wuse running use aveq"
"\n\n");
*/
rcu_read_lock();
xa_for_each(&gp->part_tbl, idx, hd) {
if (bdev_is_partition(hd) && !bdev_nr_sectors(hd))
continue;
if (queue_is_mq(gp->queue))
inflight = blk_mq_in_flight(gp->queue, hd);
else
inflight = part_in_flight(hd);
if (inflight) {
part_stat_lock();
update_io_ticks(hd, jiffies, true);
part_stat_unlock();
}
part_stat_read_all(hd, &stat);
seq_printf(seqf, "%4d %7d %pg "
"%lu %lu %lu %u "
"%lu %lu %lu %u "
"%u %u %u "
"%lu %lu %lu %u "
"%lu %u"
"\n",
MAJOR(hd->bd_dev), MINOR(hd->bd_dev), hd,
stat.ios[STAT_READ],
stat.merges[STAT_READ],
stat.sectors[STAT_READ],
(unsigned int)div_u64(stat.nsecs[STAT_READ],
NSEC_PER_MSEC),
stat.ios[STAT_WRITE],
stat.merges[STAT_WRITE],
stat.sectors[STAT_WRITE],
(unsigned int)div_u64(stat.nsecs[STAT_WRITE],
NSEC_PER_MSEC),
inflight,
jiffies_to_msecs(stat.io_ticks),
(unsigned int)div_u64(stat.nsecs[STAT_READ] +
stat.nsecs[STAT_WRITE] +
stat.nsecs[STAT_DISCARD] +
stat.nsecs[STAT_FLUSH],
NSEC_PER_MSEC),
stat.ios[STAT_DISCARD],
stat.merges[STAT_DISCARD],
stat.sectors[STAT_DISCARD],
(unsigned int)div_u64(stat.nsecs[STAT_DISCARD],
NSEC_PER_MSEC),
stat.ios[STAT_FLUSH],
(unsigned int)div_u64(stat.nsecs[STAT_FLUSH],
NSEC_PER_MSEC)
);
}
rcu_read_unlock();
return 0;
}
static const struct seq_operations diskstats_op = {
.start = disk_seqf_start,
.next = disk_seqf_next,
.stop = disk_seqf_stop,
.show = diskstats_show
};
static int __init proc_genhd_init(void)
{
proc_create_seq("diskstats", 0, NULL, &diskstats_op);
proc_create_seq("partitions", 0, NULL, &partitions_op);
return 0;
}
module_init(proc_genhd_init);
#endif /* CONFIG_PROC_FS */
dev_t part_devt(struct gendisk *disk, u8 partno)
{
struct block_device *part;
dev_t devt = 0;
rcu_read_lock();
part = xa_load(&disk->part_tbl, partno);
if (part)
devt = part->bd_dev;
rcu_read_unlock();
return devt;
}
struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
struct lock_class_key *lkclass)
{
struct gendisk *disk;
disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
if (!disk)
return NULL;
if (bioset_init(&disk->bio_split, BIO_POOL_SIZE, 0, 0))
goto out_free_disk;
disk->bdi = bdi_alloc(node_id);
if (!disk->bdi)
goto out_free_bioset;
/* bdev_alloc() might need the queue, set before the first call */
disk->queue = q;
disk->part0 = bdev_alloc(disk, 0);
if (!disk->part0)
goto out_free_bdi;
disk->node_id = node_id;
mutex_init(&disk->open_mutex);
xa_init(&disk->part_tbl);
if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL))
goto out_destroy_part_tbl;
if (blkcg_init_disk(disk))
goto out_erase_part0;
rand_initialize_disk(disk);
disk_to_dev(disk)->class = &block_class;
disk_to_dev(disk)->type = &disk_type;
device_initialize(disk_to_dev(disk));
inc_diskseq(disk);
q->disk = disk;
lockdep_init_map(&disk->lockdep_map, "(bio completion)", lkclass, 0);
#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
INIT_LIST_HEAD(&disk->slave_bdevs);
#endif
return disk;
out_erase_part0:
xa_erase(&disk->part_tbl, 0);
out_destroy_part_tbl:
xa_destroy(&disk->part_tbl);
disk->part0->bd_disk = NULL;
iput(disk->part0->bd_inode);
out_free_bdi:
bdi_put(disk->bdi);
out_free_bioset:
bioset_exit(&disk->bio_split);
out_free_disk:
kfree(disk);
return NULL;
}
struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass)
{
struct request_queue *q;
struct gendisk *disk;
q = blk_alloc_queue(node);
if (!q)
return NULL;
disk = __alloc_disk_node(q, node, lkclass);
if (!disk) {
blk_put_queue(q);
return NULL;
}
set_bit(GD_OWNS_QUEUE, &disk->state);
return disk;
}
EXPORT_SYMBOL(__blk_alloc_disk);
/**
* put_disk - decrements the gendisk refcount
* @disk: the struct gendisk to decrement the refcount for
*
* This decrements the refcount for the struct gendisk. When this reaches 0
* we'll have disk_release() called.
*
* Note: for blk-mq disk put_disk must be called before freeing the tag_set
* when handling probe errors (that is before add_disk() is called).
*
* Context: Any context, but the last reference must not be dropped from
* atomic context.
*/
void put_disk(struct gendisk *disk)
{
if (disk)
put_device(disk_to_dev(disk));
}
EXPORT_SYMBOL(put_disk);
static void set_disk_ro_uevent(struct gendisk *gd, int ro)
{
char event[] = "DISK_RO=1";
char *envp[] = { event, NULL };
if (!ro)
event[8] = '0';
kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
}
/**
* set_disk_ro - set a gendisk read-only
* @disk: gendisk to operate on
* @read_only: %true to set the disk read-only, %false set the disk read/write
*
* This function is used to indicate whether a given disk device should have its
* read-only flag set. set_disk_ro() is typically used by device drivers to
* indicate whether the underlying physical device is write-protected.
*/
void set_disk_ro(struct gendisk *disk, bool read_only)
{
if (read_only) {
if (test_and_set_bit(GD_READ_ONLY, &disk->state))
return;
} else {
if (!test_and_clear_bit(GD_READ_ONLY, &disk->state))
return;
}
set_disk_ro_uevent(disk, read_only);
}
EXPORT_SYMBOL(set_disk_ro);
void inc_diskseq(struct gendisk *disk)
{
disk->diskseq = atomic64_inc_return(&diskseq);
}
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