From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx124.postini.com [74.125.245.124]) by kanga.kvack.org (Postfix) with SMTP id 344F36B004D for ; Sun, 4 Nov 2012 10:25:03 -0500 (EST) Received: by mail-pa0-f41.google.com with SMTP id fa10so3709616pad.14 for ; Sun, 04 Nov 2012 07:25:02 -0800 (PST) From: Jiang Liu Subject: [ACPIHP PATCH part4 8/9] ACPI/processor: serialize call to acpi_map/unmap_lsapic Date: Sun, 4 Nov 2012 23:24:01 +0800 Message-Id: <1352042642-7306-9-git-send-email-jiang.liu@huawei.com> In-Reply-To: <1352042642-7306-1-git-send-email-jiang.liu@huawei.com> References: <1352042642-7306-1-git-send-email-jiang.liu@huawei.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Rafael J . Wysocki" , Yinghai Lu , Tony Luck , Yasuaki Ishimatsu , Wen Congyang , Tang Chen , Taku Izumi , Bjorn Helgaas Cc: Jiang Liu , Kenji Kaneshige , Huang Ying , Bob Moore , Len Brown , "Srivatsa S . Bhat" , Yijing Wang , Hanjun Guo , Jiang Liu , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org Function acpi_map_lsapic() is used to allocate CPU id for hot-added CPUs and acpi_unmap_lsapic() is used to free CPU id for hot-removed CPUs. But currently there's no mechanism to serialze the CPU id allocation/free process, which may cause wrong CPU id assignment when handling concurrent CPU online/offline operations. So introuce a mutex to serialize CPU id allocation/free. Signed-off-by: Jiang Liu --- drivers/acpi/processor_driver.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c index 9a02210..6dbce2f 100644 --- a/drivers/acpi/processor_driver.c +++ b/drivers/acpi/processor_driver.c @@ -108,6 +108,7 @@ static struct acpi_driver acpi_processor_driver = { .drv.pm = &acpi_processor_pm, }; +static DEFINE_MUTEX(acpi_processor_mutex); static DEFINE_PER_CPU(void *, processor_device_array); DEFINE_PER_CPU(struct acpi_processor *, processors); @@ -668,7 +669,9 @@ static void acpi_processor_reset(struct acpi_device *device, struct acpi_process acpi_processor_unlink(device, pr); put_online_cpus(); arch_unregister_cpu(pr->id); + mutex_lock(&acpi_processor_mutex); acpi_unmap_lsapic(pr->id); + mutex_unlock(&acpi_processor_mutex); pr->id = -1; } @@ -703,14 +706,18 @@ static int acpi_processor_pre_configure(struct acpi_device *device, if (pr->apic_id == -1) return result; + mutex_lock(&acpi_processor_mutex); result = acpi_map_lsapic(device->handle, pr->apic_id, &pr->id); + mutex_unlock(&acpi_processor_mutex); if (result) return result; BUG_ON((pr->id >= nr_cpu_ids) || (pr->id < 0)); result = arch_register_cpu(pr->id, 1); if (result) { + mutex_lock(&acpi_processor_mutex); acpi_unmap_lsapic(pr->id); + mutex_unlock(&acpi_processor_mutex); pr->id = -1; return result; } -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org