From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754960AbbKCPRB (ORCPT ); Tue, 3 Nov 2015 10:17:01 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44479 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754678AbbKCPQv (ORCPT ); Tue, 3 Nov 2015 10:16:51 -0500 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 3/4] watchdog: remove {get|put}_online_cpus() from watchdog_{park|unpark}_threads() Date: Tue, 3 Nov 2015 16:21:00 +0100 Message-Id: <1446564061-3379-4-git-send-email-uobergfe@redhat.com> In-Reply-To: <1446564061-3379-1-git-send-email-uobergfe@redhat.com> References: <1446564061-3379-1-git-send-email-uobergfe@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org watchdog_{park|unpark}_threads() are now called in code paths that protect themselves against CPU hotplug, so {get|put}_online_cpus() calls are redundant and can be removed. Signed-off-by: Ulrich Obergfell --- kernel/watchdog.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 13fdda1..84c4744 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -683,33 +683,35 @@ static struct smp_hotplug_thread watchdog_threads = { * be parked and the watchdog threads of other CPUs can still be runnable. * Callers are expected to handle this special condition as appropriate in * their context. + * + * This function may only be called in a context that is protected against + * races with CPU hotplug - for example, via get_online_cpus(). */ static int watchdog_park_threads(void) { int cpu, ret = 0; - get_online_cpus(); for_each_watchdog_cpu(cpu) { ret = kthread_park(per_cpu(softlockup_watchdog, cpu)); if (ret) break; } - put_online_cpus(); return ret; } /* * unpark all watchdog threads that are specified in 'watchdog_cpumask' + * + * This function may only be called in a context that is protected against + * races with CPU hotplug - for example, via get_online_cpus(). */ static void watchdog_unpark_threads(void) { int cpu; - get_online_cpus(); for_each_watchdog_cpu(cpu) kthread_unpark(per_cpu(softlockup_watchdog, cpu)); - put_online_cpus(); } /* -- 1.7.11.7