Commit 38dbb7dd authored by Jens Axboe's avatar Jens Axboe
Browse files

blk-cgroup: don't quiesce the queue on policy activate/deactivate 



There's no potential harm in quiescing the queue, but it also doesn't
buy us anything. And we can't run the queue async for policy
deactivate, since we could be in the path of tearing the queue down.
If we schedule an async run of the queue at that time, we're racing
with queue teardown AFTER having we've already torn most of it down.

Reported-by: default avatarOmar Sandoval <osandov@fb.com>
Fixes: 4d199c6f ("blk-cgroup: ensure that we clear the stop bit on quiesced queues")
Tested-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 6c0ca7ae

block/blk-cgroup.c

+8 −12
Original line number Diff line number Diff line
@@ -1223,10 +1223,9 @@ int blkcg_activate_policy(struct request_queue *q, 
	if (blkcg_policy_enabled(q, pol))

		return 0;



	if (q->mq_ops) {

	if (q->mq_ops)

		blk_mq_freeze_queue(q);

		blk_mq_quiesce_queue(q);

	} else

	else

		blk_queue_bypass_start(q);

pd_prealloc:

	if (!pd_prealloc) {
@@ -1265,10 +1264,9 @@ pd_prealloc: 


	spin_unlock_irq(q->queue_lock);

out_bypass_end:

	if (q->mq_ops) {

	if (q->mq_ops)

		blk_mq_unfreeze_queue(q);

		blk_mq_start_stopped_hw_queues(q, true);

	} else

	else

		blk_queue_bypass_end(q);

	if (pd_prealloc)

		pol->pd_free_fn(pd_prealloc);
@@ -1292,10 +1290,9 @@ void blkcg_deactivate_policy(struct request_queue *q, 
	if (!blkcg_policy_enabled(q, pol))

		return;



	if (q->mq_ops) {

	if (q->mq_ops)

		blk_mq_freeze_queue(q);

		blk_mq_quiesce_queue(q);

	} else

	else

		blk_queue_bypass_start(q);



	spin_lock_irq(q->queue_lock);
@@ -1318,10 +1315,9 @@ void blkcg_deactivate_policy(struct request_queue *q, 


	spin_unlock_irq(q->queue_lock);



	if (q->mq_ops) {

	if (q->mq_ops)

		blk_mq_unfreeze_queue(q);

		blk_mq_start_stopped_hw_queues(q, true);

	} else

	else

		blk_queue_bypass_end(q);

}

EXPORT_SYMBOL_GPL(blkcg_deactivate_policy);

CRA Git | Maintained and supported by SUSTech CRA and CCSE