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block: Drop spurious might_sleep() from blk_put_queue()

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Dan reports the following smatch detected the following:

  block/blk-cgroup.c:1863 blkcg_schedule_throttle() warn: sleeping in atomic context

caused by blkcg_schedule_throttle() calling blk_put_queue() in an
non-sleepable context.

blk_put_queue() acquired might_sleep() in 63f93fd6fa ("block: mark
blk_put_queue as potentially blocking") which transferred the might_sleep()
from blk_free_queue().

blk_free_queue() acquired might_sleep() in e8c7d14ac6 ("block: revert back
to synchronous request_queue removal") while turning request_queue removal
synchronous. However, this isn't necessary as nothing in the free path
actually requires sleeping.

It's pretty unusual to require a sleeping context in a put operation and
it's not needed in the first place. Let's drop it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lkml.kernel.org/r/Y7g3L6fntnTtOm63@kili
Cc: Christoph Hellwig <hch@lst.de>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Fixes: e8c7d14ac6 ("block: revert back to synchronous request_queue removal") # v5.9+
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/Y7iFwjN+XzWvLv3y@slm.duckdns.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Tejun Heo 2023-01-06 10:34:10 -10:00 committed by Jens Axboe
parent b2b50d5721
commit 49e4d04f04
1 changed files with 0 additions and 3 deletions
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3
block/blk-core.c
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@ -283,12 +283,9 @@ static void blk_free_queue(struct request_queue *q)
*
* Decrements the refcount of the request_queue and free it when the refcount
* reaches 0.
*
* Context: Can sleep.
*/
void blk_put_queue(struct request_queue *q)
{
might_sleep();
if (refcount_dec_and_test(&q->refs))
blk_free_queue(q);
}