From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966287AbbBDOi3 (ORCPT ); Wed, 4 Feb 2015 09:38:29 -0500 Received: from terminus.zytor.com ([198.137.202.10]:38816 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966224AbbBDOiX (ORCPT ); Wed, 4 Feb 2015 09:38:23 -0500 Date: Wed, 4 Feb 2015 06:37:46 -0800 From: tip-bot for Nicholas Mc Guire Message-ID: Cc: hpa@zytor.com, der.herr@hofr.at, peterz@infradead.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org, mingo@kernel.org Reply-To: peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, tglx@linutronix.de, der.herr@hofr.at, hpa@zytor.com In-Reply-To: <1421467534-22834-1-git-send-email-der.herr@hofr.at> References: <1421467534-22834-1-git-send-email-der.herr@hofr.at> To: linux-tip-commits@vger.kernel.org Subject: [tip:locking/core] sched/completion: Remove unnecessary -> wait.lock serialization when reading completion state Git-Commit-ID: de30ec47302c101c7badc8fe687641fd75e596e7 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 Commit-ID: de30ec47302c101c7badc8fe687641fd75e596e7 Gitweb: http://git.kernel.org/tip/de30ec47302c101c7badc8fe687641fd75e596e7 Author: Nicholas Mc Guire AuthorDate: Sat, 17 Jan 2015 05:05:34 +0100 Committer: Ingo Molnar CommitDate: Wed, 4 Feb 2015 07:57:36 +0100 sched/completion: Remove unnecessary ->wait.lock serialization when reading completion state Signed-off-by: Nicholas Mc Guire Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1421467534-22834-1-git-send-email-der.herr@hofr.at Signed-off-by: Ingo Molnar --- kernel/sched/completion.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c index 607f852..9d1fe32d 100644 --- a/kernel/sched/completion.c +++ b/kernel/sched/completion.c @@ -288,13 +288,6 @@ EXPORT_SYMBOL(try_wait_for_completion); */ bool completion_done(struct completion *x) { - unsigned long flags; - int ret = 1; - - spin_lock_irqsave(&x->wait.lock, flags); - if (!x->done) - ret = 0; - spin_unlock_irqrestore(&x->wait.lock, flags); - return ret; + return !!ACCESS_ONCE(x->done); } EXPORT_SYMBOL(completion_done);