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authorMing Lei <ming.lei@redhat.com>2017-06-18 23:24:27 +0300
committerJens Axboe <axboe@kernel.dk>2017-06-18 23:24:27 +0300
commitf4560ffe8cec1361b1021d81aca6a4173f8e7c87 (patch)
tree957cae770ed234d2e03fef8a6e458296f011369e /include/linux/blk-mq.h
parentf660174e8bcdb2bf99129f9f7c86e5fc0e830f85 (diff)
downloadlinux-f4560ffe8cec1361b1021d81aca6a4173f8e7c87.tar.xz
blk-mq: use QUEUE_FLAG_QUIESCED to quiesce queue
It is required that no dispatch can happen any more once blk_mq_quiesce_queue() returns, and we don't have such requirement on APIs of stopping queue. But blk_mq_quiesce_queue() still may not block/drain dispatch in the the case of BLK_MQ_S_START_ON_RUN, so use the new introduced flag of QUEUE_FLAG_QUIESCED and evaluate it inside RCU read-side critical sections for fixing this issue. Also blk_mq_quiesce_queue() is implemented via stopping queue, which limits its uses, and easy to cause race, because any queue restart in other paths may break blk_mq_quiesce_queue(). With the introduced flag of QUEUE_FLAG_QUIESCED, we don't need to depend on stopping queue for quiescing any more. Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/blk-mq.h')
-rw-r--r--include/linux/blk-mq.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 787d8a2a2ac6..de6536c14ae7 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -268,6 +268,10 @@ void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues);
*/
static inline void blk_mq_quiesce_queue_nowait(struct request_queue *q)
{
+ spin_lock_irq(q->queue_lock);
+ queue_flag_set(QUEUE_FLAG_QUIESCED, q);
+ spin_unlock_irq(q->queue_lock);
+
blk_mq_stop_hw_queues(q);
}