From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932418Ab1KDWXD (ORCPT ); Fri, 4 Nov 2011 18:23:03 -0400 Received: from mga02.intel.com ([134.134.136.20]:9875 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754527Ab1KDWVO (ORCPT ); Fri, 4 Nov 2011 18:21:14 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.67,352,1309762800"; d="scan'208";a="71337192" From: "Fenghua Yu" To: "Thomas Gleixner" , "H Peter Anvin" , "Ingo Molnar" , "Linus Torvalds" , "Andrew Morton" , "Tony Luck" , "Suresh B Siddha" , "Len Brown" , "Srivatsa S. Bhat" , Peter Zijlstra Cc: "linux-kernel" , "Fenghua Yu" Subject: [PATCH 2/9] kernel/cpu.c: Add arch dependent cpu map update functions Date: Fri, 4 Nov 2011 15:03:54 -0700 Message-Id: <1320444241-834-3-git-send-email-fenghua.yu@intel.com> X-Mailer: git-send-email 1.7.2 In-Reply-To: <1320444241-834-1-git-send-email-fenghua.yu@intel.com> References: <1320444241-834-1-git-send-email-fenghua.yu@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Fenghua Yu Because resume from hibernate and suspend always starts from CPU0 on x86 BIOS, we need to check if CPU0 is online before hibernate or suspend. This causes a race condition on cpu_online_map. To cope with the race condition, we add arch_cpu_maps_update_begin() and arch_cpu_maps_update_done() during cpu_down() and cpu_up(). The functions are empty on non x86 platforms and are overriden on x86 platforms with real functions to deal with the race condition. Signed-off-by: Fenghua Yu --- kernel/cpu.c | 12 ++++++++++++ 1 files changed, 12 insertions(+), 0 deletions(-) diff --git a/kernel/cpu.c b/kernel/cpu.c index 12b7458..4d80365 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -20,6 +20,14 @@ /* Serializes the updates to cpu_online_mask, cpu_present_mask */ static DEFINE_MUTEX(cpu_add_remove_lock); +void __weak arch_cpu_maps_update_begin(void) +{ +} + +void __weak arch_cpu_maps_update_done(void) +{ +} + /* * The following two API's must be used when attempting * to serialize the updates to cpu_online_mask, cpu_present_mask. @@ -274,6 +282,7 @@ int __ref cpu_down(unsigned int cpu) int err; cpu_maps_update_begin(); + arch_cpu_maps_update_begin(); if (cpu_hotplug_disabled) { err = -EBUSY; @@ -284,6 +293,7 @@ int __ref cpu_down(unsigned int cpu) out: cpu_maps_update_done(); + arch_cpu_maps_update_done(); return err; } EXPORT_SYMBOL(cpu_down); @@ -367,6 +377,7 @@ int __cpuinit cpu_up(unsigned int cpu) #endif cpu_maps_update_begin(); + arch_cpu_maps_update_begin(); if (cpu_hotplug_disabled) { err = -EBUSY; @@ -377,6 +388,7 @@ int __cpuinit cpu_up(unsigned int cpu) out: cpu_maps_update_done(); + arch_cpu_maps_update_done(); return err; } -- 1.6.0.3