blk-mq: fix potential deadlock while nr_requests grown

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[ Upstream commit b86433721f ]

Allocate and free sched_tags while queue is freezed can deadlock[1],
this is a long term problem, hence allocate memory before freezing
queue and free memory after queue is unfreezed.

[1] https://lore.kernel.org/all/0659ea8d-a463-47c8-9180-43c719e106eb@linux.ibm.com/
Fixes: e3a2b3f931 ("blk-mq: allow changing of queue depth through sysfs")

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Yu Kuai 2025-09-10 16:04:43 +08:00 • committed by Greg Kroah-Hartman

parent b75c7a8020

commit 8d26acf847

3 changed files with 34 additions and 22 deletions

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22

block/blk-mq.c

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5

block/blk-mq.h

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29

block/blk-sysfs.c

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