From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759322AbcDMLgg (ORCPT ); Wed, 13 Apr 2016 07:36:36 -0400 Received: from terminus.zytor.com ([198.137.202.10]:56138 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759250AbcDMLgc (ORCPT ); Wed, 13 Apr 2016 07:36:32 -0400 Date: Wed, 13 Apr 2016 04:35:50 -0700 From: tip-bot for Davidlohr Bueso Message-ID: Cc: linux-edac@vger.kernel.org, dbueso@suse.de, mingo@kernel.org, tony.luck@intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, bp@suse.de, tglx@linutronix.de, dave@stgolabs.net, peterz@infradead.org Reply-To: linux-edac@vger.kernel.org, dbueso@suse.de, mingo@kernel.org, tony.luck@intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org, bp@suse.de, torvalds@linux-foundation.org, dave@stgolabs.net, peterz@infradead.org, tglx@linutronix.de In-Reply-To: <1459929916-12852-3-git-send-email-bp@alien8.de> References: <1458602396-840-1-git-send-email-dave@stgolabs.net> <1459929916-12852-3-git-send-email-bp@alien8.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:ras/core] x86/mce: Remove explicit smp_rmb() when starting CPUs sync Git-Commit-ID: bf92b1feb658f6a262daf3a87d790997a1dca0ff X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: bf92b1feb658f6a262daf3a87d790997a1dca0ff Gitweb: http://git.kernel.org/tip/bf92b1feb658f6a262daf3a87d790997a1dca0ff Author: Davidlohr Bueso AuthorDate: Wed, 6 Apr 2016 10:05:15 +0200 Committer: Ingo Molnar CommitDate: Wed, 13 Apr 2016 10:54:23 +0200 x86/mce: Remove explicit smp_rmb() when starting CPUs sync mce_start() has an explicit smp_wmb() to serialize writes to global_nwo and mce_callin. However, atomic_inc_return() implies barriers on both sides of the call, as such simply rely on this full SMP barrier. Signed-off-by: Davidlohr Bueso Signed-off-by: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: linux-edac Link: http://lkml.kernel.org/r/1458602396-840-1-git-send-email-dave@stgolabs.net Link: http://lkml.kernel.org/r/1459929916-12852-3-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/mcheck/mce.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index f0c921b..6b7039c 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -830,9 +830,9 @@ static int mce_start(int *no_way_out) atomic_add(*no_way_out, &global_nwo); /* - * global_nwo should be updated before mce_callin + * Rely on the implied barrier below, such that global_nwo + * is updated before mce_callin. */ - smp_wmb(); order = atomic_inc_return(&mce_callin); /*