Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751219AbbLUHW0 (ORCPT ); Mon, 21 Dec 2015 02:22:26 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55800 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750949AbbLUHWY (ORCPT ); Mon, 21 Dec 2015 02:22:24 -0500 Date: Mon, 21 Dec 2015 09:22:18 +0200 From: "Michael S. Tsirkin" To: Peter Zijlstra Cc: Andrew Cooper , Jason Wang , Rusty Russell , qemu-devel@nongnu.org, Alexander Duyck , linux-kernel@vger.kernel.org, David Vrabel , xen-devel@lists.xenproject.org, Boris Ostrovsky , virtualization@lists.linux-foundation.org, Arnd Bergmann , linux-arch@vger.kernel.org Subject: [PATCH RFC] smp_store_mb should use smp_mb Message-ID: <20151221091130-mutt-send-email-mst@redhat.com> References: <1450347932-16325-1-git-send-email-mst@redhat.com> <20151217105238.GA6375@twins.programming.kicks-ass.net> <20151217131554-mutt-send-email-mst@redhat.com> <20151217135726.GA6344@twins.programming.kicks-ass.net> <20151217161124-mutt-send-email-mst@redhat.com> <20151217143910.GD6344@twins.programming.kicks-ass.net> <20151220105146-mutt-send-email-mst@redhat.com> <5676E047.3010808@citrix.com> <20151220195944.GT6344@twins.programming.kicks-ass.net> <20151221085947-mutt-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151221085947-mutt-send-email-mst@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2910 Lines: 76 On some architectures 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 --- Note: I'm guessing an ack from arch maintainers will be needed, but I'm working on a bigger cleanup moving a bunch of duplicated code into asm-generic/barrier.h which depends on this, so not Cc'ing widely yet. Please Ack if appropriate but do not merge yet. diff --git a/arch/ia64/include/asm/barrier.h b/arch/ia64/include/asm/barrier.h index df896a1..425552b 100644 --- a/arch/ia64/include/asm/barrier.h +++ b/arch/ia64/include/asm/barrier.h @@ -77,7 +77,7 @@ do { \ ___p1; \ }) -#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) /* * The group barrier in front of the rsm & ssm are necessary to ensure diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h index 0eca6ef..4f0169e 100644 --- a/arch/powerpc/include/asm/barrier.h +++ b/arch/powerpc/include/asm/barrier.h @@ -34,7 +34,7 @@ #define rmb() __asm__ __volatile__ ("sync" : : : "memory") #define wmb() __asm__ __volatile__ ("sync" : : : "memory") -#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) #ifdef __SUBARCH_HAS_LWSYNC # define SMPWMB LWSYNC diff --git a/arch/s390/include/asm/barrier.h b/arch/s390/include/asm/barrier.h index d68e11e..6c1d8b5 100644 --- a/arch/s390/include/asm/barrier.h +++ b/arch/s390/include/asm/barrier.h @@ -36,7 +36,7 @@ #define smp_mb__before_atomic() smp_mb() #define smp_mb__after_atomic() smp_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) #define smp_store_release(p, v) \ do { \ diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h index b42afad..0f45f93 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/