From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754857AbdBET3E (ORCPT + 2 others); Sun, 5 Feb 2017 14:29:04 -0500 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:28545 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754828AbdBET3B (ORCPT ); Sun, 5 Feb 2017 14:29:01 -0500 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Christian Borntraeger , Willy Tarreau Subject: [PATCH 3.10 278/319] kernel: Change ASSIGN_ONCE(val, x) to WRITE_ONCE(x, val) Date: Sun, 5 Feb 2017 20:21:40 +0100 Message-Id: <1486322541-8206-179-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1486322541-8206-1-git-send-email-w@1wt.eu> References: <1486322541-8206-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: From: Christian Borntraeger commit 43239cbe79fc369f5d2160bd7f69e28b5c50a58c upstream. Feedback has shown that WRITE_ONCE(x, val) is easier to use than ASSIGN_ONCE(val,x). There are no in-tree users yet, so lets change it for 3.19. Signed-off-by: Christian Borntraeger Acked-by: Peter Zijlstra Acked-by: Davidlohr Bueso Acked-by: Paul E. McKenney [wt: backported only for next patch] Signed-off-by: Willy Tarreau --- include/linux/compiler.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 9df1978..236a4e3 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -208,7 +208,7 @@ static __always_inline void __read_once_size(volatile void *p, void *res, int si } } -static __always_inline void __assign_once_size(volatile void *p, void *res, int size) +static __always_inline void __write_once_size(volatile void *p, void *res, int size) { switch (size) { case 1: *(volatile __u8 *)p = *(__u8 *)res; break; @@ -228,15 +228,15 @@ static __always_inline void __assign_once_size(volatile void *p, void *res, int /* * Prevent the compiler from merging or refetching reads or writes. The * compiler is also forbidden from reordering successive instances of - * READ_ONCE, ASSIGN_ONCE and ACCESS_ONCE (see below), but only when the + * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the * compiler is aware of some particular ordering. One way to make the * compiler aware of ordering is to put the two invocations of READ_ONCE, - * ASSIGN_ONCE or ACCESS_ONCE() in different C statements. + * WRITE_ONCE or ACCESS_ONCE() in different C statements. * * In contrast to ACCESS_ONCE these two macros will also work on aggregate * data types like structs or unions. If the size of the accessed data * type exceeds the word size of the machine (e.g., 32 bits or 64 bits) - * READ_ONCE() and ASSIGN_ONCE() will fall back to memcpy and print a + * READ_ONCE() and WRITE_ONCE() will fall back to memcpy and print a * compile-time warning. * * Their two major use cases are: (1) Mediating communication between @@ -250,8 +250,8 @@ static __always_inline void __assign_once_size(volatile void *p, void *res, int #define READ_ONCE(x) \ ({ typeof(x) __val; __read_once_size(&x, &__val, sizeof(__val)); __val; }) -#define ASSIGN_ONCE(val, x) \ - ({ typeof(x) __val; __val = val; __assign_once_size(&x, &__val, sizeof(__val)); __val; }) +#define WRITE_ONCE(x, val) \ + ({ typeof(x) __val; __val = val; __write_once_size(&x, &__val, sizeof(__val)); __val; }) #endif /* __KERNEL__ */ -- 2.8.0.rc2.1.gbe9624a