From: Bart Van Assche <bvanassche@acm.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Bart Van Assche <bvanassche@acm.org>,
Jianchao Wang <jianchao.w.wang@oracle.com>,
Hannes Reinecke <hare@suse.com>,
Johannes Thumshirn <jthumshirn@suse.de>
Subject: [PATCH v11 6/8] block: Allow unfreezing of a queue while requests are in progress
Date: Wed, 26 Sep 2018 14:01:08 -0700 [thread overview]
Message-ID: <20180926210110.20362-7-bvanassche@acm.org> (raw)
In-Reply-To: <20180926210110.20362-1-bvanassche@acm.org>
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>
---
block/blk-mq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 85a1c1a59c72..96d501e8663c 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -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);
}
}
--
2.19.0.605.g01d371f741-goog
next prev parent reply other threads:[~2018-09-26 21:01 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-26 21:01 [PATCH v11 0/8] blk-mq: Implement runtime power management Bart Van Assche
2018-09-26 21:01 ` [PATCH v11 1/8] block: Move power management code into a new source file Bart Van Assche
2018-09-26 21:01 ` [PATCH v11 2/8] block, scsi: Change the preempt-only flag into a counter Bart Van Assche
2018-09-26 21:01 ` [PATCH v11 3/8] block: Split blk_pm_add_request() and blk_pm_put_request() Bart Van Assche
2018-09-26 21:01 ` [PATCH v11 4/8] block: Schedule runtime resume earlier Bart Van Assche
2018-09-26 21:01 ` [PATCH v11 5/8] percpu-refcount: Introduce percpu_ref_resurrect() Bart Van Assche
2018-09-26 21:01 ` Bart Van Assche [this message]
2018-09-26 21:01 ` [PATCH v11 7/8] block: Make blk_get_request() block for non-PM requests while suspended Bart Van Assche
2018-09-26 21:01 ` [PATCH v11 8/8] blk-mq: Enable support for runtime power management Bart Van Assche
2018-09-26 21:12 ` [PATCH v11 0/8] blk-mq: Implement " Jens Axboe
2018-09-26 21:14 ` Martin K. Petersen
2018-09-26 21:22 ` Jens Axboe
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