From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754823AbbL3NpC (ORCPT ); Wed, 30 Dec 2015 08:45:02 -0500 Received: from mout.kundenserver.de ([217.72.192.74]:50837 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753991AbbL3No7 (ORCPT ); Wed, 30 Dec 2015 08:44:59 -0500 From: Arnd Bergmann To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , linux-arch@vger.kernel.org, Andrew Cooper , virtualization@lists.linux-foundation.org, Stefano Stabellini Subject: Re: [PATCH 08/34] asm-generic: smp_store_mb should use smp_mb Date: Wed, 30 Dec 2015 14:44:21 +0100 Message-ID: <5946017.BCmPrpGMuh@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1451473761-30019-9-git-send-email-mst@redhat.com> References: <1451473761-30019-1-git-send-email-mst@redhat.com> <1451473761-30019-9-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:UGdBPEs8DFo/fGWViiB6uFc0LF/jmAhznJJKgk+EPi7qRFKp5Lx 8ihWExpPzRFAnA0OIqwSbUaye429zAVPdH/6AY343HHlHjO9EpQfCfOfcPDjI1sxtCdBKjd WVzdHzTBrrRxQwDUPTqTFdlz3cuSY5r83c2ODL0f1/jU0m2JuAzWk5nnuF1t/XXlKeT1xYX LiFpWOj/t1cMxNvz2UMKg== X-UI-Out-Filterresults: notjunk:1;V01:K0:KSJT82sublo=:4gx1ipame4eV53dFnzOsta gbfhbXbb+p42zxjovQU7OPQOSIehnT8ajgnBB3DJHsy+znUAyaajF4cnntTe0X+Qb+oJUqlqY 6Hjoe26PpNT7B4gO46GKbbYFN6338FvMSYnFWoSFT2Wkm+nGrtyPCIEAOIzYd6x1KuKMW1tOY rSlWg43hBO9P/rUv67i+0hGDDsU/cFrT8UurDt/M77pQPN6ix0GouQ4+BC1kh1oeA8KuOt5aK D3dPYjBLlaJPVFGwp+qvS9mmhVgh1zsJ5QQmahx04lNg2CXvP74p2dSftT93Hr2cCGs4g2gRW 1Nec2dXaQu36Hjo3paOAGkqaZuRFfgMUzczCRTZc4o/3Y5Mg7szhCf/4F3orHQWsSCdhMYV8L HNS1NWYy0xiKAxzjSUEobwO2XfyOgxbtOPEaLkkYZ8zC27BrCsypeLZmCdKB+ymbkYz6pq8Bp PoXCumnNIdIQDr7x+a+tFJ2LgKWVwBdWAT7Cv/fqaqNWK9+Ud1VzA4rORrF24WWOMYg4ih0Zb OolWOrkq5crPx/dD/LkzI6N0NWw9VVcTMgIUQB6IP1trGTTE2ah0IPCWU7/GNlNwOqlmM0/wG kO+2sDQEhqsnnigEQZji3LlwEFle+BK42kDzf++KlmmzMkznrjS9LdnXcm25lm1tbSanUve6q 7lF63XLh/fovY4SCajcZZhKEROOLPc6P79b347W1sWCwsGkA12+GwjEAlAjylLCxwsn8ifRF1 fZzBn51Tws5Zgdtg Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 30 December 2015 15:24:47 Michael S. Tsirkin wrote: > asm-generic variant of smp_store_mb() calls mb() which is stronger > than implied by both the name and the documentation. > > smp_store_mb is only used by core kernel code at the moment, so > we know no one mis-uses it for an MMIO barrier. > Make it call smp_mb consistently before some arch-specific > code uses it as such by mistake. > > Signed-off-by: Michael S. Tsirkin > --- > include/asm-generic/barrier.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h > index 538f8d1..987b2e0 100644 > --- a/include/asm-generic/barrier.h > +++ b/include/asm-generic/barrier.h > @@ -93,7 +93,7 @@ > #endif /* CONFIG_SMP */ > > #ifndef smp_store_mb > -#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); mb(); } while (0) > +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); smp_mb(); } while (0) > #endif > > #ifndef smp_mb__before_atomic > The same patch is already in the tip tree scheduled for 4.5 as d5a73cadf3fd ("lcoking/barriers, arch: Use smp barriers in smp_store_release()"). I think you can drop your version. arnd