Commit bdd63160 authored Sep 26, 2018 by Bart Van Assche Committed by Jens Axboe Sep 26, 2018

block: Allow unfreezing of a queue while requests are in progress



A later patch will call blk_freeze_queue_start() followed by
blk_mq_unfreeze_queue() without waiting for q_usage_counter to drop
to zero. Make sure that this doesn't cause a kernel warning to appear
by switching from percpu_ref_reinit() to percpu_ref_resurrect(). The
former namely requires that the refcount it operates on is zero.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jianchao Wang <jianchao.w.wang@oracle.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 18c9a6bb

block/blk-mq.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -198,7 +198,7 @@ void blk_mq_unfreeze_queue(struct request_queue *q)
		freeze_depth = atomic_dec_return(&q->mq_freeze_depth);
		WARN_ON_ONCE(freeze_depth < 0);
		if (!freeze_depth) {
		percpu_ref_reinit(&q->q_usage_counter);
		percpu_ref_resurrect(&q->q_usage_counter);
		wake_up_all(&q->mq_freeze_wq);
		}
		}

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