From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754697Ab0IVOcF (ORCPT ); Wed, 22 Sep 2010 10:32:05 -0400 Received: from e6.ny.us.ibm.com ([32.97.182.146]:59842 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754221Ab0IVOcD (ORCPT ); Wed, 22 Sep 2010 10:32:03 -0400 Message-ID: <4C9A1360.6030800@austin.ibm.com> Date: Wed, 22 Sep 2010 09:32:00 -0500 From: Nathan Fontenot User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.12) Gecko/20100915 Thunderbird/3.0.8 MIME-Version: 1.0 To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@ozlabs.org CC: Greg KH , KAMEZAWA Hiroyuki , Dave Hansen Subject: [PATCH 4/8] Add mutex for adding/removing memory blocks References: <4C9A0F8F.2030409@austin.ibm.com> In-Reply-To: <4C9A0F8F.2030409@austin.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a new mutex for use in adding and removing of memory blocks. This is needed to avoid any race conditions in which the same memory block could be added and removed at the same time. Signed-off-by: Nathan Fontenot --- drivers/base/memory.c | 7 +++++++ 1 file changed, 7 insertions(+) Index: linux-next/drivers/base/memory.c =================================================================== --- linux-next.orig/drivers/base/memory.c 2010-09-21 12:36:45.000000000 -0500 +++ linux-next/drivers/base/memory.c 2010-09-21 12:37:03.000000000 -0500 @@ -27,6 +27,8 @@ #include #include +static DEFINE_MUTEX(mem_sysfs_mutex); + #define MEMORY_CLASS_NAME "memory" static struct sysdev_class memory_sysdev_class = { @@ -485,6 +487,8 @@ static int add_memory_block(int nid, str if (!mem) return -ENOMEM; + mutex_lock(&mem_sysfs_mutex); + mem->start_phys_index = __section_nr(section); mem->state = state; atomic_inc(&mem->section_count); @@ -508,6 +512,7 @@ static int add_memory_block(int nid, str ret = register_mem_sect_under_node(mem, nid); } + mutex_unlock(&mem_sysfs_mutex); return ret; } @@ -516,6 +521,7 @@ int remove_memory_block(unsigned long no { struct memory_block *mem; + mutex_lock(&mem_sysfs_mutex); mem = find_memory_block(section); if (atomic_dec_and_test(&mem->section_count)) { @@ -528,6 +534,7 @@ int remove_memory_block(unsigned long no unregister_memory(mem, section); } + mutex_unlock(&mem_sysfs_mutex); return 0; }