When poll request is timed out, it is removed from the poll list,
but not completed, so the request is leaked, and never get chance
to complete.
Fix the issue by ending it in timeout handler.
Fixes: 0a593fbbc2 ("null_blk: poll queue support")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220413084836.1571995-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove goto labels and use direct returns as error unwinding code only
needs to free t_page variable if we alloc_pages() call fails as having
two labels for one kfree() can be avoided easily.
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220222152852.26043-3-kch@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Only caller of null_alloc_page() is null_insert_page() unconditionally
sets only parameter to GFP_NOIO and that is statically hard-coded in
null_blk. There is no point in having statically hardcoded function
parameter.
Remove the unnecessary parameter gfp_flags and adjust the code, so it
can retain existing behavior null_alloc_page() with GFP_NOIO.
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220222152852.26043-2-kch@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Only caller of alloc_cmd() is null_submit_bio() unconditionally sets
second parameter to true and that is statically hard-coded in null_blk.
There is no point in having statically hardcoded function parameter.
Remove the unnecessary parameter can_wait and adjust the code so it
can retain existing behavior of waiting when we don't get valid
nullb_cmd from __alloc_cmd() in alloc_cmd().
The restructured code avoids multiple return statements, multiple
calls to __alloc_cmd() and resulting a fast path call to
prepare_to_wait() due to removal of first alloc_cmd() call.
Follow the pattern that we have in bio_alloc() to set the structure
members in the structure allocation function in alloc_cmd() and pass
bio to initialize newly allocated cmd->bio member.
Follow the pattern in copy_to_nullb() to use result of one function call
(null_cache_active()) to be used as a parameter to another function call
(null_insert_page()), use result of alloc_cmd() as a first parameter to
the null_handle_cmd() in null_submit_bio() function. This allow us to
remove the local variable cmd on stack in null_submit_bio() that is in
fast path.
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Link: https://lore.kernel.org/r/20220216172945.31124-2-kch@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The function nullb_device_power_store() returns -ENOMEM when
null_add_dev() fails. null_add_dev() can fail with return value
other than -ENOMEM such as -EINVAL when Zoned Block Device option
is used, see :
nullb_device_power_store()
null_add_dev()
null_init_zoned_dev()
return -EINVAL;
When trying to load the module having -ENOMEM value returned on the
command line creates confusion when pleanty of memory is free on the
machine.
Instead of hardcoding -ENOMEM return the value of null_add_dev()
function.
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220215115951.15945-1-kch@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It isn't correct to set set->nr_maps as 3 if g_poll_queues is > 0 since
we can change it via configfs for null_blk device created there, so only
set it as 3 if active poll_queues is > 0.
Fixes divide zero exception reported by Shinichiro.
Fixes: 2bfdbe8b7e ("null_blk: allow zero poll queues")
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/r/20211224010831.1521805-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
kernel test robot reports that sparse now triggers a warning on null_blk:
>> drivers/block/null_blk/main.c:1577:55: sparse: sparse: incorrect type in argument 3 (different base types) @@ expected int ioerror @@ got restricted blk_status_t [usertype] error @@
drivers/block/null_blk/main.c:1577:55: sparse: expected int ioerror
drivers/block/null_blk/main.c:1577:55: sparse: got restricted blk_status_t [usertype] error
because blk_mq_add_to_batch() takes an integer instead of a blk_status_t.
Just cast this to an integer to silence it, null_blk is the odd one out
here since the command status is the "right" type. If we change the
function type, then we'll have do that for other callers too (existing and
future ones).
Fixes: 2385ebf38f ("block: null_blk: batched complete poll requests")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Complete poll requests via blk_mq_add_to_batch() and
blk_mq_end_request_batch(), so that we can cover batched complete
code path by running null_blk test.
Meantime this way shows ~14% IOPS boost on 't/io_uring /dev/nullb0'
in my test.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203081703.3506020-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There isn't any reason to not allow zero poll queues from user
viewpoint.
Also sometimes we need to compare io poll between poll mode and irq
mode, so not allowing poll queues is bad.
Fixes: 15dfc662ef ("null_blk: Fix handling of submit_queues and poll_queues attributes")
Cc: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203023935.3424042-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Just use the disk attached to the request_queue instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211126121802.2090656-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
All modern drivers can support extra partitions using the extended
dev_t. In fact except for the ioctl method drivers never even see
partitions in normal operation.
So remove the GENHD_FL_EXT_DEVT and allow extra partitions for all
block devices that do support partitions, and require those that
do not support partitions to explicit disallow them using
GENHD_FL_NO_PART.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211122130625.1136848-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This manually reverts commit 27290b469051 ("null_blk: suppress invalid
partition info"). The message in that commit log can't appearch as
the flag is never checked during probing, and there is no good reason
to treat null_blk special in /proc/partitions.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211122130625.1136848-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 0a593fbbc2 ("null_blk: poll queue support") introduced the poll
queue feature to null_blk. After this change, null_blk device has both
submit queues and poll queues, and null_map_queues() callback maps the
both queues for corresponding hardware contexts. The commit also added
the device configuration attribute 'poll_queues' in same manner as the
existing attribute 'submit_queues'. These attributes allow to modify the
numbers of queues. However, when the new values are stored to these
attributes, the values are just handled only for the corresponding
queue. When number of submit_queue is updated, number of poll_queue is
not counted, or vice versa. This caused inconsistent number of queues
and queue mapping and resulted in null-ptr-dereference. This failure was
observed in blktests block/029 and block/030.
To avoid the inconsistency, fix the attribute updates to care both
submit_queues and poll_queues. Introduce the helper function
nullb_update_nr_hw_queues() to handle stores to the both two attributes.
Add poll_queues field to the struct nullb_device to track the number in
same manner as submit_queues. Add two more fields prev_submit_queues and
prev_poll_queues to keep the previous values before change. In case the
block layer failed to update the nr_hw_queues, refer the previous values
in null_map_queues() to map queues in same manner as before change.
Also add poll_queues value checks in nullb_update_nr_hw_queues() and
null_validate_conf(). They ensure the poll_queues value of each device
is within the range from 1 to module parameter value of poll_queues.
Fixes: 0a593fbbc2 ("null_blk: poll queue support")
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/r/20211029103926.845635-1-shinichiro.kawasaki@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There's currently no way to experiment with polled IO with null_blk,
which seems like an oversight. This patch adds support for polled IO.
We keep a list of issued IOs on submit, and then process that list
when mq_ops->poll() is invoked.
A new parameter is added, poll_queues. It defaults to 1 like the
submit queues, meaning we'll have 1 poll queue available.
Fixes-by: Bart Van Assche <bvanassche@acm.org>
Fixes-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/baca710d-0f2a-16e2-60bd-b105b854e0ae@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace the blk_poll interface that requires the caller to keep a queue
and cookie from the submissions with polling based on the bio.
Polling for the bio itself leads to a few advantages:
- the cookie construction can made entirely private in blk-mq.c
- the caller does not need to remember the request_queue and cookie
separately and thus sidesteps their lifetime issues
- keeping the device and the cookie inside the bio allows to trivially
support polling BIOs remapping by stacking drivers
- a lot of code to propagate the cookie back up the submission path can
be removed entirely.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We never checked for errors on add_disk() as this function
returned void. Now that this is fixed, use the shiny new
error handling. The actual cleanup in case of error is
already handled by the caller of null_gendisk_register().
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210818144542.19305-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-21-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The error handling on a nullb->disk allocation currently jumps to
out_cleanup_disk that calls blk_cleanup_disk with a null pointer causing
a null pointer dereference issue. Fix this by jumping to out_cleanup_tags
instead.
Addresses-Coverity: ("Dereference after null check")
Fixes: 132226b301 ("null_blk: convert to blk_alloc_disk/blk_cleanup_disk")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210602100659.11058-1-colin.king@canonical.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Convert the null_blk driver to use the blk_alloc_disk and blk_cleanup_disk
helpers to simplify gendisk and request_queue allocation. Note that the
blk-mq mode is left with its own allocations scheme, to be handled later.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-26-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In null_init, null_add_dev(dev) is called.
In null_add_dev, it calls null_free_zoned_dev(dev) to free dev->zones
via kvfree(dev->zones) in out_cleanup_zone branch and returns err.
Then null_init accept the err code and then calls null_free_dev(dev).
But in null_free_dev(dev), dev->zones is freed again by
null_free_zoned_dev().
My patch set dev->zones to NULL in null_free_zoned_dev() after
kvfree(dev->zones) is called, to avoid the double free.
Fixes: 2984c8684f ("nullb: factor disk parameters")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Link: https://lore.kernel.org/r/20210426143229.7374-1-lyl2019@mail.ustc.edu.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This will enable changing the virtual boundary of null blk devices. For
now, null blk devices didn't have any restriction on the scatter/gather
elements received from the block layer. Add a module parameter and a
configfs option that will control the virtual boundary. This will
enable testing the efficiency of the block layer bounce buffer in case
a suitable application will send discontiguous IO to the given device.
Initial testing with patched FIO showed the following results (64 jobs,
128 iodepth, 1 nullb device):
IO size READ (virt=false) READ (virt=true) Write (virt=false) Write (virt=true)
---------- ------------------- ----------------- ------------------- -------------------
1k 10.7M 8482k 10.8M 8471k
2k 10.4M 8266k 10.4M 8271k
4k 10.4M 8274k 10.3M 8226k
8k 10.2M 8131k 9800k 7933k
16k 9567k 7764k 8081k 6828k
32k 8865k 7309k 5570k 5153k
64k 7695k 6586k 2682k 2617k
128k 5346k 5489k 1320k 1296k
Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Link: https://lore.kernel.org/r/20210412095523.278632-1-mgurtovoy@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Memory backed or zoned null block devices may generate actual request
timeout errors due to the submission path being blocked on memory
allocation or zone locking. Unlike fake timeouts or injected timeouts,
the request submission path will call blk_mq_complete_request() or
blk_mq_end_request() for these real timeout errors, causing a double
completion and use after free situation as the block layer timeout
handler executes blk_mq_rq_timed_out() and __blk_mq_free_request() in
blk_mq_check_expired(). This problem often triggers a NULL pointer
dereference such as:
BUG: kernel NULL pointer dereference, address: 0000000000000050
RIP: 0010:blk_mq_sched_mark_restart_hctx+0x5/0x20
...
Call Trace:
dd_finish_request+0x56/0x80
blk_mq_free_request+0x37/0x130
null_handle_cmd+0xbf/0x250 [null_blk]
? null_queue_rq+0x67/0xd0 [null_blk]
blk_mq_dispatch_rq_list+0x122/0x850
__blk_mq_do_dispatch_sched+0xbb/0x2c0
__blk_mq_sched_dispatch_requests+0x13d/0x190
blk_mq_sched_dispatch_requests+0x30/0x60
__blk_mq_run_hw_queue+0x49/0x90
process_one_work+0x26c/0x580
worker_thread+0x55/0x3c0
? process_one_work+0x580/0x580
kthread+0x134/0x150
? kthread_create_worker_on_cpu+0x70/0x70
ret_from_fork+0x1f/0x30
This problem very often triggers when running the full btrfs xfstests
on a memory-backed zoned null block device in a VM with limited amount
of memory.
Avoid this by executing blk_mq_complete_request() in null_timeout_rq()
only for commands that are marked for a fake timeout completion using
the fake_timeout boolean in struct null_cmd. For timeout errors injected
through debugfs, the timeout handler will execute
blk_mq_complete_request()i as before. This is safe as the submission
path does not execute complete requests in this case.
In null_timeout_rq(), also make sure to set the command error field to
BLK_STS_TIMEOUT and to propagate this error through to the request
completion.
Reported-by: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Tested-by: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Reviewed-by: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20210331225244.126426-1-damien.lemoal@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-5.12/block-2021-02-17' of git://git.kernel.dk/linux-block
Pull core block updates from Jens Axboe:
"Another nice round of removing more code than what is added, mostly
due to Christoph's relentless pursuit of tech debt removal/cleanups.
This pull request contains:
- Two series of BFQ improvements (Paolo, Jan, Jia)
- Block iov_iter improvements (Pavel)
- bsg error path fix (Pan)
- blk-mq scheduler improvements (Jan)
- -EBUSY discard fix (Jan)
- bvec allocation improvements (Ming, Christoph)
- bio allocation and init improvements (Christoph)
- Store bdev pointer in bio instead of gendisk + partno (Christoph)
- Block trace point cleanups (Christoph)
- hard read-only vs read-only split (Christoph)
- Block based swap cleanups (Christoph)
- Zoned write granularity support (Damien)
- Various fixes/tweaks (Chunguang, Guoqing, Lei, Lukas, Huhai)"
* tag 'for-5.12/block-2021-02-17' of git://git.kernel.dk/linux-block: (104 commits)
mm: simplify swapdev_block
sd_zbc: clear zone resources for non-zoned case
block: introduce blk_queue_clear_zone_settings()
zonefs: use zone write granularity as block size
block: introduce zone_write_granularity limit
block: use blk_queue_set_zoned in add_partition()
nullb: use blk_queue_set_zoned() to setup zoned devices
nvme: cleanup zone information initialization
block: document zone_append_max_bytes attribute
block: use bi_max_vecs to find the bvec pool
md/raid10: remove dead code in reshape_request
block: mark the bio as cloned in bio_iov_bvec_set
block: set BIO_NO_PAGE_REF in bio_iov_bvec_set
block: remove a layer of indentation in bio_iov_iter_get_pages
block: turn the nr_iovecs argument to bio_alloc* into an unsigned short
block: remove the 1 and 4 vec bvec_slabs entries
block: streamline bvec_alloc
block: factor out a bvec_alloc_gfp helper
block: move struct biovec_slab to bio.c
block: reuse BIO_INLINE_VECS for integrity bvecs
...
Use blk_queue_set_zoned() to set a nullb device zone model instead of
directly assigning the device queue zoned limit. This initialization of
the devicve zoned model as well as the setup of the queue flag
QUEUE_FLAG_ZONE_RESETALL and of the device queue elevator feature are
moved from null_init_zoned_dev() to null_register_zoned_dev() so that
the initialization of the queue limits is done when the gendisk of the
nullb device is available.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@edc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
To avoid potential compilation problems, replaced the badly written
MB_TO_SECTS() macro (missing parenthesis around the argument use) with
the inline function mb_to_sects(). And while at it, simplify the
calculation of the total number of zones of the device using the
round_up() macro.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace the gendisk pointer in struct bio with a pointer to the newly
improved struct block device. From that the gendisk can be trivially
accessed with an extra indirection, but it also allows to directly
look up all information related to partition remapping.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move null_blk driver code into the new sub-directory
drivers/block/null_blk.
Suggested-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Ming Lei