From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755420AbaHKWwJ (ORCPT ); Mon, 11 Aug 2014 18:52:09 -0400 Received: from mail-yh0-f50.google.com ([209.85.213.50]:62606 "EHLO mail-yh0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752786AbaHKWvS (ORCPT ); Mon, 11 Aug 2014 18:51:18 -0400 From: Pranith Kumar To: "Paul E. McKenney" , Peter Zijlstra , Ingo Molnar , Josh Triplett , David Howells , Masanari Iida , linux-kernel@vger.kernel.org (open list) Subject: [PATCH] doc: memory-barriers.txt: Add barrier() to provide ordering Date: Mon, 11 Aug 2014 18:51:40 -0400 Message-Id: <1407797503-24727-2-git-send-email-bobby.prani@gmail.com> X-Mailer: git-send-email 2.0.4 In-Reply-To: <1407797503-24727-1-git-send-email-bobby.prani@gmail.com> References: <1407797503-24727-1-git-send-email-bobby.prani@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the provably false case, add barrier() in both the legs of the if() condition to provide ordering. Signed-off-by: Pranith Kumar --- Documentation/memory-barriers.txt | 2 ++ 1 file changed, 2 insertions(+) diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index 41a6c9c..0f2903f 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -689,9 +689,11 @@ should do something like the following: q = ACCESS_ONCE(a); BUILD_BUG_ON(MAX <= 1); /* Order load from a with store to b. */ if (q % MAX) { + barrier(); ACCESS_ONCE(b) = p; do_something(); } else { + barrier(); ACCESS_ONCE(b) = p; do_something_else(); } -- 1.9.1