From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757397Ab1I3Q2V (ORCPT ); Fri, 30 Sep 2011 12:28:21 -0400 Received: from claw.goop.org ([74.207.240.146]:45590 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754666Ab1I3Q2T (ORCPT ); Fri, 30 Sep 2011 12:28:19 -0400 Message-ID: <4E85EE1F.7050508@goop.org> Date: Fri, 30 Sep 2011 09:28:15 -0700 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:6.0.2) Gecko/20110906 Thunderbird/6.0.2 MIME-Version: 1.0 To: Tejun Heo CC: Rusty Russell , Peter Zijlstra , Andrew Morton , Ingo Molnar , Steven Rostedt , Linux Kernel Mailing List , "H. Peter Anvin" Subject: [PATCH RFC] stop_machine: make stop_machine safe and efficient to call early X-Enigmail-Version: 1.3.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Make stop_machine() safe to call early in boot, before SMP has been set up, by simply calling the callback function directly if there's only one CPU online. Signed-off-by: Jeremy Fitzhardinge Cc: Tejun Heo Cc: Rusty Russell Cc: Peter Zijlstra Cc: Andrew Morton Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Steven Rostedt diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index ba5070c..2df15ca 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -485,6 +485,9 @@ int __stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus) .num_threads = num_online_cpus(), .active_cpus = cpus }; + if (smdata.num_threads == 1) + return (*fn)(data); + /* Set the initial state and stop all online cpus. */ set_state(&smdata, STOPMACHINE_PREPARE); return stop_cpus(cpu_online_mask, stop_machine_cpu_stop, &smdata);