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,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 3B7E0C072B1 for ; Thu, 30 May 2019 04:14:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 101DF251EB for ; Thu, 30 May 2019 04:14:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559189659; bh=Ysv2PzbbJsEvju4N7o/L7/38TGdOq5lM4hxD3RTj5H8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=EXxJ6xa2DnuP3MoScXALM2mhtL94Z8YUqE06nFcPRRvRKrIWU3NarhYieW0d90858 A9z1zjXjad66t0QBllkctAP32ORZrHkr3YSn3c9jaRCyrL5hiio+RnoTJCTf0/aL76 J2LurBf1zciA0gIxhQPxprxmi6AOrdVMdPuCZneo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730838AbfE3EOR (ORCPT ); Thu, 30 May 2019 00:14:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:41588 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730625AbfE3DQN (ORCPT ); Wed, 29 May 2019 23:16:13 -0400 Received: from localhost (ip67-88-213-2.z213-88-67.customer.algx.net [67.88.213.2]) (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 40C952449A; Thu, 30 May 2019 03:16:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559186173; bh=Ysv2PzbbJsEvju4N7o/L7/38TGdOq5lM4hxD3RTj5H8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rvejg9RO7moRctGMcQYeeZcLa5fXJFvypeeaB43YUaNhGjPuovQaSixdaViVjlfQs VWvOCpgADorGG+pA+0I4AFR72s4qSVWR1B9jAemgY/MsrKE2/4MOWxxE9kNjWDL/ie pAe0nnYxEtfc709B5xFdx6q8QHRrUI+53PYi1HWY= 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 4.19 006/276] bio: fix improper use of smp_mb__before_atomic() Date: Wed, 29 May 2019 20:02:44 -0700 Message-Id: <20190530030523.764119003@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190530030523.133519668@linuxfoundation.org> References: <20190530030523.133519668@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 @@ -257,7 +257,7 @@ 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); }