From patchwork Sun Jun 9 16:40:20 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 10983761 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3B9A8924 for ; Sun, 9 Jun 2019 16:59:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1936D2852A for ; Sun, 9 Jun 2019 16:59:11 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0D0D12889C; Sun, 9 Jun 2019 16:59:11 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 690782852A for ; Sun, 9 Jun 2019 16:59:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387614AbfFIQ7H (ORCPT ); Sun, 9 Jun 2019 12:59:07 -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 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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); }