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>
