From patchwork Thu Aug 20 09:19:59 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 265292 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 258F9C433E3 for ; Thu, 20 Aug 2020 13:38:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF56720674 for ; Thu, 20 Aug 2020 13:38:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597930737; bh=vUMlRPXZX8LWcxjNTSMNJN5QyXqT7sG8LtdI37FiEJg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=xDtvxnZZTBtZWBHcVItWLR9QVsA6QEf4xqcVZ5dXzMFmnVME2ON3eGtgD2XAKUhOh DDawbFcKtFdAa4sLXc008um+6vNTcAdKZoJBmG/zKbM50Zpl0nzN9ksMJkYPSAkn8U HvvuiNXBnBHzFBx9osed7FNZ1VGPcJIp3V5sV5UM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727809AbgHTJan (ORCPT ); Thu, 20 Aug 2020 05:30:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:41544 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728169AbgHTJaa (ORCPT ); Thu, 20 Aug 2020 05:30:30 -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 D1FDE20855; Thu, 20 Aug 2020 09:30:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597915830; bh=vUMlRPXZX8LWcxjNTSMNJN5QyXqT7sG8LtdI37FiEJg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GjYlkHjqXdGJd7msDAHoN3DUSE8fAYDzdgIkBYVpjR8JdhpxQcK+I+x5nY6jXSLEB fwR6iCgNqMUm1aMaZc6Rhm/8UCrto3KvBCyON83H5DHvVUscJVHzSMndybc/EjgEKC 890j0+aRWwClrCh5Yep4Kbyg4mClPolAv82EUmwc= 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 5.8 148/232] dm rq: dont call blk_mq_queue_stopped() in dm_stop_queue() Date: Thu, 20 Aug 2020 11:19:59 +0200 Message-Id: <20200820091619.981973887@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200820091612.692383444@linuxfoundation.org> References: <20200820091612.692383444@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 85e0daabad49c..20745e2e34b94 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -70,9 +70,6 @@ void dm_start_queue(struct request_queue *q) void dm_stop_queue(struct request_queue *q) { - if (blk_mq_queue_stopped(q)) - return; - blk_mq_quiesce_queue(q); }