Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757932AbcCUXUU (ORCPT ); Mon, 21 Mar 2016 19:20:20 -0400 Received: from smtp2.provo.novell.com ([137.65.250.81]:60446 "EHLO smtp2.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751005AbcCUXUT (ORCPT ); Mon, 21 Mar 2016 19:20:19 -0400 From: Davidlohr Bueso To: bp@alien8.de, tony.luck@intel.com, mingo@kernel.org Cc: linux-kernel@vger.kernel.org, dave@stgolabs.net, Davidlohr Bueso Subject: [PATCH -tip] x86/mce: Use atomic_inc_return barrier when starting monad sync Date: Mon, 21 Mar 2016 16:19:56 -0700 Message-Id: <1458602396-840-1-git-send-email-dave@stgolabs.net> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 881 Lines: 28 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 --- 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 f0c921b03e42..6b7039c166b8 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); /* -- 2.1.4