Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756842AbcC2KiN (ORCPT ); Tue, 29 Mar 2016 06:38:13 -0400 Received: from terminus.zytor.com ([198.137.202.10]:47082 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753100AbcC2KiK (ORCPT ); Tue, 29 Mar 2016 06:38:10 -0400 Date: Tue, 29 Mar 2016 03:37:35 -0700 From: tip-bot for Frederic Weisbecker Message-ID: Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, fweisbec@gmail.com, akpm@linux-foundation.org, hpa@zytor.com Reply-To: peterz@infradead.org, fweisbec@gmail.com, akpm@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, mingo@kernel.org In-Reply-To: <1458830281-4255-4-git-send-email-fweisbec@gmail.com> References: <1458830281-4255-4-git-send-email-fweisbec@gmail.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:core/urgent] locking/atomic, sched: Unexport fetch_or() Git-Commit-ID: 5529578a27288d11d4d15635c258c6dde0f0fb10 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: 3391 Lines: 106 Commit-ID: 5529578a27288d11d4d15635c258c6dde0f0fb10 Gitweb: http://git.kernel.org/tip/5529578a27288d11d4d15635c258c6dde0f0fb10 Author: Frederic Weisbecker AuthorDate: Thu, 24 Mar 2016 15:38:01 +0100 Committer: Ingo Molnar CommitDate: Tue, 29 Mar 2016 11:52:11 +0200 locking/atomic, sched: Unexport fetch_or() This patch functionally reverts: 5fd7a09cfb8c ("atomic: Export fetch_or()") During the merge Linus observed that the generic version of fetch_or() was messy: " This makes the ugly "fetch_or()" macro that the scheduler used internally a new generic helper, and does a bad job at it. " e23604edac2a Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Now that we have introduced atomic_fetch_or(), fetch_or() is only used by the scheduler in order to deal with thread_info flags which type can vary across architectures. Lets confine fetch_or() back to the scheduler so that we encourage future users to use the more robust and well typed atomic_t version instead. While at it, fetch_or() gets robustified, pasting improvements from a previous patch by Ingo Molnar that avoids needless expression re-evaluations in the loop. Reported-by: Linus Torvalds Signed-off-by: Frederic Weisbecker Cc: Andrew Morton Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1458830281-4255-4-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar --- include/linux/atomic.h | 21 --------------------- kernel/sched/core.c | 18 ++++++++++++++++++ 2 files changed, 18 insertions(+), 21 deletions(-) diff --git a/include/linux/atomic.h b/include/linux/atomic.h index 3d64c08..506c353 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -579,27 +579,6 @@ static inline int atomic_fetch_or(atomic_t *p, int mask) } #endif -/** - * fetch_or - perform *ptr |= mask and return old value of *ptr - * @ptr: pointer to value - * @mask: mask to OR on the value - * - * cmpxchg based fetch_or, macro so it works for different integer types - */ -#ifndef fetch_or -#define fetch_or(ptr, mask) \ -({ typeof(*(ptr)) __old, __val = *(ptr); \ - for (;;) { \ - __old = cmpxchg((ptr), __val, __val | (mask)); \ - if (__old == __val) \ - break; \ - __val = __old; \ - } \ - __old; \ -}) -#endif - - #ifdef CONFIG_GENERIC_ATOMIC64 #include #endif diff --git a/kernel/sched/core.c b/kernel/sched/core.c index d8465ee..8b489fc 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -321,6 +321,24 @@ static inline void init_hrtick(void) } #endif /* CONFIG_SCHED_HRTICK */ +/* + * cmpxchg based fetch_or, macro so it works for different integer types + */ +#define fetch_or(ptr, mask) \ + ({ \ + typeof(ptr) _ptr = (ptr); \ + typeof(mask) _mask = (mask); \ + typeof(*_ptr) _old, _val = *_ptr; \ + \ + for (;;) { \ + _old = cmpxchg(_ptr, _val, _val | _mask); \ + if (_old == _val) \ + break; \ + _val = _old; \ + } \ + _old; \ +}) + #if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG) /* * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,