Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755935Ab1FNJt1 (ORCPT ); Tue, 14 Jun 2011 05:49:27 -0400 Received: from hera.kernel.org ([140.211.167.34]:42171 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755908Ab1FNJtZ (ORCPT ); Tue, 14 Jun 2011 05:49:25 -0400 Date: Tue, 14 Jun 2011 09:49:10 GMT From: tip-bot for Max Asbock Message-ID: Cc: linux-kernel@vger.kernel.org, masbock@linux.vnet.ibm.com, hpa@zytor.com, mingo@redhat.com, johnstul@linux.vnet.ibm.com, tglx@linutronix.de Reply-To: mingo@redhat.com, hpa@zytor.com, masbock@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, johnstul@linux.vnet.ibm.com, tglx@linutronix.de In-Reply-To: <1307985512.4710.41.camel@w-amax.beaverton.ibm.com> References: <1307985512.4710.41.camel@w-amax.beaverton.ibm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:timers/urgent] timerfd: Fix wakeup of processes when timer is cancelled on clock change Git-Commit-ID: 1123d93963cbd2546449d4d9f0c568e323cb0ac6 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Tue, 14 Jun 2011 09:49:12 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2403 Lines: 58 Commit-ID: 1123d93963cbd2546449d4d9f0c568e323cb0ac6 Gitweb: http://git.kernel.org/tip/1123d93963cbd2546449d4d9f0c568e323cb0ac6 Author: Max Asbock AuthorDate: Mon, 13 Jun 2011 10:18:32 -0700 Committer: Thomas Gleixner CommitDate: Tue, 14 Jun 2011 11:46:14 +0200 timerfd: Fix wakeup of processes when timer is cancelled on clock change Currently processes waiting with poll on cancelable timerfd timers are not woken up when the timers are canceled. When the system time is set the clock_was_set() function calls timerfd_clock_was_set() to cancel and wake up processes waiting on potential cancelable timerfd timers. However the wake up currently has no effect because in the case of timerfd_read it is dependent on ctx->ticks not being 0. timerfd_poll also requires ctx->ticks being non zero. As a consequence processes waiting on cancelable timers only get woken up when the timers expire. This patch fixes this by incrementing ctx->ticks before calling wake_up. Signed-off-by: Max Asbock Cc: kay.sievers@vrfy.org Cc: virtuoso@slind.org Cc: johnstul Link: http://lkml.kernel.org/r/1307985512.4710.41.camel@w-amax.beaverton.ibm.com Signed-off-by: Thomas Gleixner --- fs/timerfd.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-) diff --git a/fs/timerfd.c b/fs/timerfd.c index f67acbd..dffeb37 100644 --- a/fs/timerfd.c +++ b/fs/timerfd.c @@ -61,7 +61,9 @@ static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr) /* * Called when the clock was set to cancel the timers in the cancel - * list. + * list. This will wake up processes waiting on these timers. The + * wake-up requires ctx->ticks to be non zero, therefore we increment + * it before calling wake_up_locked(). */ void timerfd_clock_was_set(void) { @@ -76,6 +78,7 @@ void timerfd_clock_was_set(void) spin_lock_irqsave(&ctx->wqh.lock, flags); if (ctx->moffs.tv64 != moffs.tv64) { ctx->moffs.tv64 = KTIME_MAX; + ctx->ticks++; wake_up_locked(&ctx->wqh); } spin_unlock_irqrestore(&ctx->wqh.lock, flags); -- 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/