Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756775AbcC2Kh0 (ORCPT ); Tue, 29 Mar 2016 06:37:26 -0400 Received: from terminus.zytor.com ([198.137.202.10]:47038 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752669AbcC2KhZ (ORCPT ); Tue, 29 Mar 2016 06:37:25 -0400 Date: Tue, 29 Mar 2016 03:36:47 -0700 From: tip-bot for Frederic Weisbecker Message-ID: Cc: hpa@zytor.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, fweisbec@gmail.com, torvalds@linux-foundation.org, peterz@infradead.org, mingo@kernel.org, tglx@linutronix.de Reply-To: akpm@linux-foundation.org, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org, peterz@infradead.org, fweisbec@gmail.com In-Reply-To: <1458830281-4255-2-git-send-email-fweisbec@gmail.com> References: <1458830281-4255-2-git-send-email-fweisbec@gmail.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:core/urgent] locking/atomic: Introduce atomic_fetch_or() Git-Commit-ID: 5acba71e18833b9d06686b3751598bfa263a3ac3 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 Content-Length: 1929 Lines: 60 Commit-ID: 5acba71e18833b9d06686b3751598bfa263a3ac3 Gitweb: http://git.kernel.org/tip/5acba71e18833b9d06686b3751598bfa263a3ac3 Author: Frederic Weisbecker AuthorDate: Thu, 24 Mar 2016 15:37:59 +0100 Committer: Ingo Molnar CommitDate: Tue, 29 Mar 2016 11:52:11 +0200 locking/atomic: Introduce atomic_fetch_or() This is deemed to replace the type generic fetch_or() which brings a lot of issues such as macro induced block variable aliasing and sloppy types. Not to mention fetch_or() doesn't refer to any namespace, adding even more confusion. So lets provide an atomic_t version. Current and next users of fetch_or() are thus encouraged to use atomic_t. Signed-off-by: Frederic Weisbecker Cc: Andrew Morton Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1458830281-4255-2-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar --- include/linux/atomic.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/include/linux/atomic.h b/include/linux/atomic.h index df4f369..3d64c08 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -559,6 +559,27 @@ static inline int atomic_dec_if_positive(atomic_t *v) #endif /** + * atomic_fetch_or - perform *p |= mask and return old value of *p + * @p: pointer to atomic_t + * @mask: mask to OR on the atomic_t + */ +#ifndef atomic_fetch_or +static inline int atomic_fetch_or(atomic_t *p, int mask) +{ + int old, val = atomic_read(p); + + for (;;) { + old = atomic_cmpxchg(p, val, val | mask); + if (old == val) + break; + val = old; + } + + return old; +} +#endif + +/** * fetch_or - perform *ptr |= mask and return old value of *ptr * @ptr: pointer to value * @mask: mask to OR on the value