From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C6CFC433E1 for ; Thu, 20 Aug 2020 09:54:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D3978208DB for ; Thu, 20 Aug 2020 09:54:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597917276; bh=JnNbhAP2AQk4xvVJqWvvnnyW0+wwq4Gfhgkon2rtHL0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=QZ0woNu4eYrffyAKTQbGtkGTLKaOBG9SG32v1yJhDwg1VNQAtX8gOBIJ1qh1vMiSA 2n/sV1Gp7SZuiPtyAHZDk4Dy9WkHBboMUyyUmZMumzYQRbnL/ZGr2KyMAq1bmXsZZo oWhuvbcXDbQvmWdMHaUpQWoA0RttIwNxeAelzI44= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730139AbgHTJye (ORCPT ); Thu, 20 Aug 2020 05:54:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:36676 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730105AbgHTJyR (ORCPT ); Thu, 20 Aug 2020 05:54:17 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A73732067C; Thu, 20 Aug 2020 09:54:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597917257; bh=JnNbhAP2AQk4xvVJqWvvnnyW0+wwq4Gfhgkon2rtHL0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sTG593gs+2GxJ0QYbH/SciMJpvm4ssAJJAxpCrzLFTyH1zbyA+qmSBxV1TaIOx6ki HXj7GMhj7rOUrx+lgqKSfRySdurcQoHhcZvuIEeANeSX6qbDmD0+2QafW1uFnO9nBV WhqEjHMHiwUjU7z9dbl4XgJ4wXWZHcXa0pzjhJQU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ming Lei , Mike Snitzer , Sasha Levin Subject: [PATCH 4.19 59/92] dm rq: dont call blk_mq_queue_stopped() in dm_stop_queue() Date: Thu, 20 Aug 2020 11:21:44 +0200 Message-Id: <20200820091540.691298635@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200820091537.490965042@linuxfoundation.org> References: <20200820091537.490965042@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ming Lei [ Upstream commit e766668c6cd49d741cfb49eaeb38998ba34d27bc ] dm_stop_queue() only uses blk_mq_quiesce_queue() so it doesn't formally stop the blk-mq queue; therefore there is no point making the blk_mq_queue_stopped() check -- it will never be stopped. In addition, even though dm_stop_queue() actually tries to quiesce hw queues via blk_mq_quiesce_queue(), checking with blk_queue_quiesced() to avoid unnecessary queue quiesce isn't reliable because: the QUEUE_FLAG_QUIESCED flag is set before synchronize_rcu() and dm_stop_queue() may be called when synchronize_rcu() from another blk_mq_quiesce_queue() is in-progress. Fixes: 7b17c2f7292ba ("dm: Fix a race condition related to stopping and starting queues") Signed-off-by: Ming Lei Signed-off-by: Mike Snitzer Signed-off-by: Sasha Levin --- drivers/md/dm-rq.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index 4d36373e1c0f0..9fde174ce3961 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -95,9 +95,6 @@ static void dm_old_stop_queue(struct request_queue *q) static void dm_mq_stop_queue(struct request_queue *q) { - if (blk_mq_queue_stopped(q)) - return; - blk_mq_quiesce_queue(q); } -- 2.25.1