From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:35230 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751281AbdFFPY2 (ORCPT ); Tue, 6 Jun 2017 11:24:28 -0400 From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org, Christoph Hellwig Cc: Bart Van Assche , Ming Lei Subject: [PATCH v5 10/12] blk-mq: don't stop queue for quiescing Date: Tue, 6 Jun 2017 23:22:08 +0800 Message-Id: <20170606152210.22806-11-ming.lei@redhat.com> In-Reply-To: <20170606152210.22806-1-ming.lei@redhat.com> References: <20170606152210.22806-1-ming.lei@redhat.com> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org 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 --- 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); } /* -- 2.9.4