From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752869AbbI1Ukc (ORCPT ); Mon, 28 Sep 2015 16:40:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57453 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752246AbbI1Uka (ORCPT ); Mon, 28 Sep 2015 16:40:30 -0400 From: Ulrich Obergfell To: linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, dzickus@redhat.com, atomlin@redhat.com, uobergfe@redhat.com Subject: [PATCH 3/5] watchdog: implement error handling in update_watchdog_all_cpus() and callers Date: Mon, 28 Sep 2015 22:44:10 +0200 Message-Id: <1443473052-3053-4-git-send-email-uobergfe@redhat.com> In-Reply-To: <1443473052-3053-1-git-send-email-uobergfe@redhat.com> References: <1443473052-3053-1-git-send-email-uobergfe@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org update_watchdog_all_cpus() now passes errors from watchdog_park_threads() up to functions in the call chain. This allows watchdog_enable_all_cpus() and proc_watchdog_update() to handle such errors too. Signed-off-by: Ulrich Obergfell --- kernel/watchdog.c | 30 +++++++++++++++++++++++------- 1 file changed, 23 insertions(+), 7 deletions(-) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index eb9527c..457113c 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -731,10 +731,17 @@ void lockup_detector_resume(void) mutex_unlock(&watchdog_proc_mutex); } -static void update_watchdog_all_cpus(void) +static int update_watchdog_all_cpus(void) { - watchdog_park_threads(); + int ret; + + ret = watchdog_park_threads(); + if (ret) + return ret; + watchdog_unpark_threads(); + + return 0; } static int watchdog_enable_all_cpus(void) @@ -753,9 +760,17 @@ static int watchdog_enable_all_cpus(void) * Enable/disable the lockup detectors or * change the sample period 'on the fly'. */ - update_watchdog_all_cpus(); + err = update_watchdog_all_cpus(); + + if (err) { + watchdog_disable_all_cpus(); + pr_err("Failed to update lockup detectors, disabled\n"); + } } + if (err) + watchdog_enabled = 0; + return err; } @@ -851,12 +866,13 @@ static int proc_watchdog_common(int which, struct ctl_table *table, int write, } while (cmpxchg(&watchdog_enabled, old, new) != old); /* - * Update the run state of the lockup detectors. - * Restore 'watchdog_enabled' on failure. + * Update the run state of the lockup detectors. There is _no_ + * need to check the value returned by proc_watchdog_update() + * and to restore the previous value of 'watchdog_enabled' as + * both lockup detectors are disabled if proc_watchdog_update() + * returns an error. */ err = proc_watchdog_update(); - if (err) - watchdog_enabled = old; } out: mutex_unlock(&watchdog_proc_mutex); -- 1.7.11.7