From patchwork Sat May 27 14:21:24 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 9751933 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1862D602F0 for ; Sat, 27 May 2017 14:22:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0BB3328425 for ; Sat, 27 May 2017 14:22:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F410D28475; Sat, 27 May 2017 14:22:41 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A1E3D28425 for ; Sat, 27 May 2017 14:22:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932152AbdE0OWl (ORCPT ); Sat, 27 May 2017 10:22:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59122 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932076AbdE0OWk (ORCPT ); Sat, 27 May 2017 10:22:40 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 373A583F45; Sat, 27 May 2017 14:22:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 373A583F45 Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=ming.lei@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 373A583F45 Received: from localhost (ovpn-12-80.pek2.redhat.com [10.72.12.80]) by smtp.corp.redhat.com (Postfix) with ESMTP id 38C2818340; Sat, 27 May 2017 14:22:32 +0000 (UTC) From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org, Christoph Hellwig Cc: Bart Van Assche , Ming Lei Subject: [PATCH v2 6/8] blk-mq: don't stop queue for quiescing Date: Sat, 27 May 2017 22:21:24 +0800 Message-Id: <20170527142126.26079-7-ming.lei@redhat.com> In-Reply-To: <20170527142126.26079-1-ming.lei@redhat.com> References: <20170527142126.26079-1-ming.lei@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Sat, 27 May 2017 14:22:40 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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. Signed-off-by: Ming Lei --- block/blk-mq.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 032045841856..84cce67caee3 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -168,8 +168,6 @@ 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); @@ -198,7 +196,12 @@ 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); + /* + * During quiescing, requests can be inserted + * to scheduler's queue or sw queue, so we run + * queues for dispatching these requests. + */ + blk_mq_start_hw_queues(q); } EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);