From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757960Ab0EJXb3 (ORCPT ); Mon, 10 May 2010 19:31:29 -0400 Received: from kroah.org ([198.145.64.141]:33295 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932486Ab0EJWwk (ORCPT ); Mon, 10 May 2010 18:52:40 -0400 X-Mailbox-Line: From gregkh@kvm.kroah.org Mon May 10 15:33:24 2010 Message-Id: <20100510223324.601081932@kvm.kroah.org> User-Agent: quilt/0.48-4.4 Date: Mon, 10 May 2010 15:32:51 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Vaidyanathan Srinivasan , Gautham R Shenoy , Benjamin Herrenschmidt Subject: [080/117] powerpc: Move checks in pseries_mach_cpu_die() In-Reply-To: <20100510223700.GA18404@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.33-stable review patch. If anyone has any objections, please let us know. ------------------ From: Vaidyanathan Srinivasan commit 0212f2602a38e740d5a96aba4cebfc2ebc993ecf upstream. Rearrange condition checks for better code readability and prevention of possible race conditions when preferred_offline_state can potentially change during the execution of pseries_mach_cpu_die(). The patch will make pseries_mach_cpu_die() put cpu in one of the consistent states and not hit the run over BUG() Signed-off-by: Vaidyanathan Srinivasan Cc: Gautham R Shenoy Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/platforms/pseries/hotplug-cpu.c | 30 +++++++++++++-------------- 1 file changed, 15 insertions(+), 15 deletions(-) --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c @@ -140,25 +140,25 @@ static void pseries_mach_cpu_die(void) if (!get_lppaca()->shared_proc) get_lppaca()->donate_dedicated_cpu = 0; get_lppaca()->idle = 0; - } - if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) { - unregister_slb_shadow(hwcpu, __pa(get_slb_shadow())); + if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) { + unregister_slb_shadow(hwcpu, __pa(get_slb_shadow())); - /* - * Call to start_secondary_resume() will not return. - * Kernel stack will be reset and start_secondary() - * will be called to continue the online operation. - */ - start_secondary_resume(); + /* + * Call to start_secondary_resume() will not return. + * Kernel stack will be reset and start_secondary() + * will be called to continue the online operation. + */ + start_secondary_resume(); + } + } - } else if (get_preferred_offline_state(cpu) == CPU_STATE_OFFLINE) { + /* Requested state is CPU_STATE_OFFLINE at this point */ + WARN_ON(get_preferred_offline_state(cpu) != CPU_STATE_OFFLINE); - set_cpu_current_state(cpu, CPU_STATE_OFFLINE); - unregister_slb_shadow(hard_smp_processor_id(), - __pa(get_slb_shadow())); - rtas_stop_self(); - } + set_cpu_current_state(cpu, CPU_STATE_OFFLINE); + unregister_slb_shadow(hwcpu, __pa(get_slb_shadow())); + rtas_stop_self(); /* Should never get here... */ BUG();