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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 A2DF1C04E87 for ; Mon, 20 May 2019 17:24:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B451216B7 for ; Mon, 20 May 2019 17:24:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amarulasolutions.com header.i=@amarulasolutions.com header.b="i+tc6wIo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392876AbfETRYm (ORCPT ); Mon, 20 May 2019 13:24:42 -0400 Received: from mail-wm1-f66.google.com ([209.85.128.66]:53801 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392873AbfETRYm (ORCPT ); Mon, 20 May 2019 13:24:42 -0400 Received: by mail-wm1-f66.google.com with SMTP id 198so163133wme.3 for ; Mon, 20 May 2019 10:24:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amarulasolutions.com; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=8JCGP2keOd1v4ZtvnJIPJLCc79LDgGj6QPJ6XqW4/pQ=; b=i+tc6wIoCAm8Fs2rzTAE6lyMnY10bwE3S7lTIkqJZ4wLp9lZCEZJRBRsM8BrFytdhh LhMP4NBM+t13gVQ+nr5MAL77FdB/RHw847SxYmWgnsV5G8YzL+7g9ryybdRAXx6qXTBL Zx0oYhcnH36ZwuiC+JJg0EMqU8kNiHG7ukSDk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=8JCGP2keOd1v4ZtvnJIPJLCc79LDgGj6QPJ6XqW4/pQ=; b=E9tV0ljdu3sZY3KxonevAkwNbjLWjU54NDZmpHlSI/eiTUMDSoslGNxXcomqkShk1v JkwrbIIFS6hWOBLm3m+17Hy0XU9K/in5ulDqNeH71St096QPtzjnwKcwideoy2gs8edY S9o2Ilj7ZTMVElVQbERFVXmv8OEjC64y9jNi8ig7vAH9jmHyQhaCOLjGoIv2jwX4ooQA iAloKC5l+jDZma+lj1+eZu2JvnY3DXOeWKVp/0jNuoS5xGppcCLr9m2GbVlErqywRP71 r3QDLFj9RDxXDg9DyqwWuIvyXF5cug88uaOjXdmSWSp74ljyHUJ/hMjSLC8tPJKlAEgO 2+2g== X-Gm-Message-State: APjAAAVt/2hideUUCEkUlRpEcUupXJM5b9b1Hnj/2teF2mBrWOLEPhmc 5BeR5GyUh7twIWehszNVLEWj671H1P8OeA== X-Google-Smtp-Source: APXvYqxgeV4LGEt7Jk6ZUdmwfJ/W+F8V+ZdFAtR5wPJjhjlfgOX2onUnuiC23YystDlcOv8EoDDY4Q== X-Received: by 2002:a1c:f50a:: with SMTP id t10mr185633wmh.86.1558373080090; Mon, 20 May 2019 10:24:40 -0700 (PDT) Received: from localhost.localdomain ([91.253.179.221]) by smtp.gmail.com with ESMTPSA id b12sm180021wmg.27.2019.05.20.10.24.38 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 20 May 2019 10:24:39 -0700 (PDT) From: Andrea Parri To: linux-kernel@vger.kernel.org Cc: Andrea Parri , stable@vger.kernel.org, Jens Axboe , Ming Lei , linux-block@vger.kernel.org, "Paul E. McKenney" , Peter Zijlstra Subject: [PATCH 2/4] bio: fix improper use of smp_mb__before_atomic() Date: Mon, 20 May 2019 19:23:56 +0200 Message-Id: <1558373038-5611-3-git-send-email-andrea.parri@amarulasolutions.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1558373038-5611-1-git-send-email-andrea.parri@amarulasolutions.com> References: <1558373038-5611-1-git-send-email-andrea.parri@amarulasolutions.com> Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This barrier only applies to the read-modify-write operations; in particular, it does not apply to the atomic_set() primitive. Replace the barrier with an smp_mb(). Fixes: dac56212e8127 ("bio: skip atomic inc/dec of ->bi_cnt for most use cases") Cc: stable@vger.kernel.org Reported-by: "Paul E. McKenney" Reported-by: Peter Zijlstra Signed-off-by: Andrea Parri Reviewed-by: Ming Lei Cc: Jens Axboe Cc: Ming Lei Cc: linux-block@vger.kernel.org Cc: "Paul E. McKenney" Cc: Peter Zijlstra --- include/linux/bio.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/bio.h b/include/linux/bio.h index ea73df36529ad..0f23b56826403 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -210,7 +210,7 @@ static inline void bio_cnt_set(struct bio *bio, unsigned int count) { if (count != 1) { bio->bi_flags |= (1 << BIO_REFFED); - smp_mb__before_atomic(); + smp_mb(); } atomic_set(&bio->__bi_cnt, count); } -- 2.7.4