Messages in this thread Patch in this message | | | Date | Fri, 6 Jan 2023 10:34:10 -1000 | From | Tejun Heo <> | Subject | [PATCH block/for-6.2-fixes] 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 63f93fd6fa57 ("block: mark blk_put_queue as potentially blocking") which transferred the might_sleep() from blk_free_queue().
blk_free_queue() acquired might_sleep() in e8c7d14ac6c3 ("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: e8c7d14ac6c3 ("block: revert back to synchronous request_queue removal") # v5.9+ -- block/blk-core.c | 3 --- 1 file changed, 3 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c index 9321767470dc..b5098355d8b2 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -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); }
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