From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031922AbdDTL2R (ORCPT ); Thu, 20 Apr 2017 07:28:17 -0400 Received: from terminus.zytor.com ([65.50.211.136]:48735 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031903AbdDTL2I (ORCPT ); Thu, 20 Apr 2017 07:28:08 -0400 Date: Thu, 20 Apr 2017 04:25:28 -0700 From: tip-bot for Sebastian Andrzej Siewior Message-ID: Cc: linux-kernel@vger.kernel.org, bigeasy@linutronix.de, hpa@zytor.com, mingo@kernel.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org Reply-To: linux-kernel@vger.kernel.org, bigeasy@linutronix.de, mingo@kernel.org, hpa@zytor.com, rostedt@goodmis.org, tglx@linutronix.de, peterz@infradead.org In-Reply-To: <20170418170553.531067939@linutronix.de> References: <20170418170553.531067939@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:smp/hotplug] cpu/hotplug: Use stop_machine_cpuslocked() in takedown_cpu() Git-Commit-ID: cdcb496b285dc8e9c544107d42bd60e5bc2feffa 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: cdcb496b285dc8e9c544107d42bd60e5bc2feffa Gitweb: http://git.kernel.org/tip/cdcb496b285dc8e9c544107d42bd60e5bc2feffa Author: Sebastian Andrzej Siewior AuthorDate: Tue, 18 Apr 2017 19:04:56 +0200 Committer: Thomas Gleixner CommitDate: Thu, 20 Apr 2017 13:08:55 +0200 cpu/hotplug: Use stop_machine_cpuslocked() in takedown_cpu() takedown_cpu() is a cpu hotplug function invoking stop_machine(). The cpu hotplug machinery holds the hotplug lock for write. stop_machine() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use stop_machine_cpuslocked() to avoid the nested call. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: Steven Rostedt Link: http://lkml.kernel.org/r/20170418170553.531067939@linutronix.de --- kernel/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/cpu.c b/kernel/cpu.c index 92e5a91..f932e68 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -701,7 +701,7 @@ static int takedown_cpu(unsigned int cpu) /* * So now all preempt/rcu users must observe !cpu_active(). */ - err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu)); + err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); if (err) { /* CPU refused to die */ irq_unlock_sparse();