From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:53416 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932076AbdE0OWc (ORCPT ); Sat, 27 May 2017 10:22:32 -0400 From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org, Christoph Hellwig Cc: Bart Van Assche , Ming Lei Subject: [PATCH v2 5/8] blk-mq: update comments on blk_mq_quiesce_queue() Date: Sat, 27 May 2017 22:21:23 +0800 Message-Id: <20170527142126.26079-6-ming.lei@redhat.com> In-Reply-To: <20170527142126.26079-1-ming.lei@redhat.com> References: <20170527142126.26079-1-ming.lei@redhat.com> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org Actually what we want to get from blk_mq_quiesce_queue() isn't only to wait for completion of all ongoing .queue_rq(). In the typical context of canceling requests, we need to make sure that the following is done in the dispatch path before starting to cancel requests: - failed dispatched request is finished - busy dispatched request is requeued, and the STARTED flag is cleared So update comment to keep code, doc and our expection consistent. Signed-off-by: Ming Lei --- block/blk-mq.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 470ee5514ea9..032045841856 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -155,12 +155,12 @@ void blk_mq_unfreeze_queue(struct request_queue *q) EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); /** - * blk_mq_quiesce_queue() - wait until all ongoing queue_rq calls have finished + * blk_mq_quiesce_queue() - wait until all ongoing dispatching have finished * @q: request queue. * * Note: this function does not prevent that the struct request end_io() - * callback function is invoked. Additionally, it is not prevented that - * new queue_rq() calls occur unless the queue has been stopped first. + * callback function is invoked. Once this function is returned, we make + * sure no dispatching can happen. */ void blk_mq_quiesce_queue(struct request_queue *q) { -- 2.9.4