From 49e4d04f0486117ac57a97890eb1db6d52bf82b3 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Fri, 6 Jan 2023 10:34:10 -1000
Subject: [PATCH] block: Drop spurious might_sleep() from blk_put_queue()
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+
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>
---
block/blk-core.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 9321767470dc5..b5098355d8b27 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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