[PATCH v5 10/12] blk-mq: don't stop queue for quiescing
From: Ming Lei <hidden>
Date: 2017-06-06 15:24:28
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
Queue can be started by other blk-mq APIs and can be used in different cases, this limits uses of blk_mq_quiesce_queue() if it is based on stopping queue, and make its usage very difficult, especially users have to use the stop queue APIs carefully for avoiding to break blk_mq_quiesce_queue(). We have applied the QUIESCED flag for draining and blocking dispatch, so it isn't necessary to stop queue any more. After stopping queue is removed, blk_mq_quiesce_queue() can be used safely and easily, then users won't worry about queue restarting during quiescing at all. Reviewed-by: Bart Van Assche <redacted> Signed-off-by: Ming Lei <redacted> --- block/blk-mq.c | 9 +++------ include/linux/blk-mq.h | 2 -- 2 files changed, 3 insertions(+), 8 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index abfa2b3bff74..4eb849bf1d85 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c@@ -169,11 +169,7 @@ void blk_mq_quiesce_queue(struct request_queue *q) unsigned int i; bool rcu = false; - __blk_mq_stop_hw_queues(q, true); - - spin_lock_irq(q->queue_lock); - queue_flag_set(QUEUE_FLAG_QUIESCED, q); - spin_unlock_irq(q->queue_lock); + blk_mq_quiesce_queue_nowait(q); queue_for_each_hw_ctx(q, hctx, i) { if (hctx->flags & BLK_MQ_F_BLOCKING)
@@ -199,7 +195,8 @@ void blk_mq_unquiesce_queue(struct request_queue *q) queue_flag_clear(QUEUE_FLAG_QUIESCED, q); spin_unlock_irq(q->queue_lock); - blk_mq_start_stopped_hw_queues(q, true); + /* dispatch requests which are inserted during quiescing */ + blk_mq_run_hw_queues(q, true); } EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index dc96ce3f5425..105d70630947 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h@@ -274,8 +274,6 @@ 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); } /*
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2.9.4