blk-mq: blk_mq_freeze_queue() should allow nesting

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While converting to percpu_ref for freezing, add703fda9 ("blk-mq:
use percpu_ref for mq usage count") incorrectly made
blk_mq_freeze_queue() misbehave when freezing is nested due to
percpu_ref_kill() being invoked on an already killed ref.

Fix it by making blk_mq_freeze_queue() kill and kick the queue only
for the outermost freeze attempt.  All the nested ones can simply wait
for the ref to reach zero.

While at it, remove unnecessary @wake initialization from
blk_mq_unfreeze_queue().

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

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Tejun Heo 2014-08-16 08:02:24 -04:00 • committed by Jens Axboe

parent a68aafa5b2

commit cddd5d1764

1 changed files with 8 additions and 4 deletions

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block/blk-mq.c

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