diff options
| author | Damien Le Moal <damien.lemoal@wdc.com> | 2020-11-06 20:01:41 +0900 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-11-06 09:36:42 -0700 |
| commit | e1777d099728a76a8f8090f89649aac961e7e530 (patch) | |
| tree | 27dac735a263de3ca72c7b8cdbf2c2179fd23f7e /drivers/block/null_blk.h | |
| parent | 7ae7a8de054253024624abebd86eb25c5bdaf1c8 (diff) | |
null_blk: Fix scheduling in atomic with zoned mode
Commit aa1c09cb65e2 ("null_blk: Fix locking in zoned mode") changed
zone locking to using the potentially sleeping wait_on_bit_io()
function. This is acceptable when memory backing is enabled as the
device queue is in that case marked as blocking, but this triggers a
scheduling while in atomic context with memory backing disabled.
Fix this by relying solely on the device zone spinlock for zone
information protection without temporarily releasing this lock around
null_process_cmd() execution in null_zone_write(). This is OK to do
since when memory backing is disabled, command processing does not
block and the memory backing lock nullb->lock is unused. This solution
avoids the overhead of having to mark a zoned null_blk device queue as
blocking when memory backing is unused.
This patch also adds comments to the zone locking code to explain the
unusual locking scheme.
Fixes: aa1c09cb65e2 ("null_blk: Fix locking in zoned mode")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block/null_blk.h')
| -rw-r--r-- | drivers/block/null_blk.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/block/null_blk.h b/drivers/block/null_blk.h index cfd00ad40355..c24d9b5ad81a 100644 --- a/drivers/block/null_blk.h +++ b/drivers/block/null_blk.h @@ -47,7 +47,7 @@ struct nullb_device { unsigned int nr_zones_closed; struct blk_zone *zones; sector_t zone_size_sects; - spinlock_t zone_dev_lock; + spinlock_t zone_lock; unsigned long *zone_locks; unsigned long size; /* device size in MB */ |