From 1d9e9bc6b56e1bb7e33e7e2e1b99d7088356c006 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Tue, 6 Jun 2017 23:22:08 +0800 Subject: [PATCH] blk-mq: don't stop queue for quiescing 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 Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- 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 f2a73190f60d..dbae586602f6 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 de6536c14ae7..f1bd13ae8f57 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -271,8 +271,6 @@ 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); } /* -- 2.20.1