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=-6.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH,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 C0D9CC28EBD for ; Sun, 9 Jun 2019 16:59:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9B0CC206DF for ; Sun, 9 Jun 2019 16:59:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560099553; bh=NRvK615v25GoOdRPL360NWzr60LSRHxx997j8H+H/mo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=D6JFyIOcMUrahnYmTfY3uzDtC2eftFXcOMtMjl4tNDg1wG/bJbdUedho1T8/p2GjX K49oxtUR3xrYrTlE8OxB+31JbCmmidUS8a0XH8elys43X6EGiket+gA+Kh00Re8eii F/Tpiw35/aNawVsAq3ptDiBJW/AsVJSZgan0OQhw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387627AbfFIQ7M (ORCPT ); Sun, 9 Jun 2019 12:59:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:34736 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732775AbfFIQ7H (ORCPT ); Sun, 9 Jun 2019 12:59:07 -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 14804206C3; Sun, 9 Jun 2019 16:59:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560099546; bh=NRvK615v25GoOdRPL360NWzr60LSRHxx997j8H+H/mo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KRHxLhAvXIUOIxJ+/leHOGmXSxQOdvS+lpPIPlphjzGgH1IGoFgyUCUQJR7uR+5jT mfAsRAqc1j8vGqGOniWPb03Of9QT3gD1fvf1+a9+Lw1fa6JE76y3lYEJYGA+9+pWSn wxPdTa5vc3W0SFOBTzhSFxTl+C9VYNz0LbUydbvY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Paul E. McKenney" , Peter Zijlstra , Andrea Parri , Ming Lei , Jens Axboe , linux-block@vger.kernel.org Subject: [PATCH 4.4 078/241] bio: fix improper use of smp_mb__before_atomic() Date: Sun, 9 Jun 2019 18:40:20 +0200 Message-Id: <20190609164150.022547203@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190609164147.729157653@linuxfoundation.org> References: <20190609164147.729157653@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: Andrea Parri commit f381c6a4bd0ae0fde2d6340f1b9bb0f58d915de6 upstream. 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 Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- include/linux/bio.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -290,7 +290,7 @@ static inline void bio_cnt_set(struct bi { if (count != 1) { bio->bi_flags |= (1 << BIO_REFFED); - smp_mb__before_atomic(); + smp_mb(); } atomic_set(&bio->__bi_cnt, count); }