Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756518Ab2JEC0N (ORCPT ); Thu, 4 Oct 2012 22:26:13 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:60125 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756117Ab2JEC0J (ORCPT ); Thu, 4 Oct 2012 22:26:09 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.7.4 Message-ID: <506E451E.1050403@jp.fujitsu.com> Date: Fri, 5 Oct 2012 11:25:34 +0900 From: Yasuaki Ishimatsu User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:15.0) Gecko/20120907 Thunderbird/15.0.1 MIME-Version: 1.0 To: , , , , , , , , , CC: Yasuaki Ishimatsu , , , , , , , , Subject: [PATCH 1/10] memory-hotplug : check whether memory is offline or not when removing memory References: <506E43E0.70507@jp.fujitsu.com> In-Reply-To: <506E43E0.70507@jp.fujitsu.com> Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4316 Lines: 128 When calling remove_memory(), the memory should be offline. If the function is used to online memory, kernel panic may occur. So the patch checks whether memory is offline or not. CC: David Rientjes CC: Jiang Liu CC: Len Brown CC: Christoph Lameter Cc: Minchan Kim CC: Andrew Morton CC: KOSAKI Motohiro Signed-off-by: Wen Congyang Signed-off-by: Yasuaki Ishimatsu --- drivers/base/memory.c | 39 +++++++++++++++++++++++++++++++++++++++ include/linux/memory.h | 5 +++++ mm/memory_hotplug.c | 17 +++++++++++++++-- 3 files changed, 59 insertions(+), 2 deletions(-) Index: linux-3.6/drivers/base/memory.c =================================================================== --- linux-3.6.orig/drivers/base/memory.c 2012-10-04 14:22:57.000000000 +0900 +++ linux-3.6/drivers/base/memory.c 2012-10-04 14:45:46.653585860 +0900 @@ -70,6 +70,45 @@ void unregister_memory_isolate_notifier( } EXPORT_SYMBOL(unregister_memory_isolate_notifier); +bool is_memblk_offline(unsigned long start, unsigned long size) +{ + struct memory_block *mem = NULL; + struct mem_section *section; + unsigned long start_pfn, end_pfn; + unsigned long pfn, section_nr; + + start_pfn = PFN_DOWN(start); + end_pfn = PFN_UP(start + size); + + for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { + section_nr = pfn_to_section_nr(pfn); + if (!present_section_nr(section_nr)) + continue; + + section = __nr_to_section(section_nr); + /* same memblock? */ + if (mem) + if ((section_nr >= mem->start_section_nr) && + (section_nr <= mem->end_section_nr)) + continue; + + mem = find_memory_block_hinted(section, mem); + if (!mem) + continue; + if (mem->state == MEM_OFFLINE) + continue; + + kobject_put(&mem->dev.kobj); + return false; + } + + if (mem) + kobject_put(&mem->dev.kobj); + + return true; +} +EXPORT_SYMBOL(is_memblk_offline); + /* * register_memory - Setup a sysfs device for a memory block */ Index: linux-3.6/include/linux/memory.h =================================================================== --- linux-3.6.orig/include/linux/memory.h 2012-10-02 18:00:22.000000000 +0900 +++ linux-3.6/include/linux/memory.h 2012-10-04 14:44:40.902581028 +0900 @@ -106,6 +106,10 @@ static inline int memory_isolate_notify( { return 0; } +static inline bool is_memblk_offline(unsigned long start, unsigned long size) +{ + return false; +} #else extern int register_memory_notifier(struct notifier_block *nb); extern void unregister_memory_notifier(struct notifier_block *nb); @@ -120,6 +124,7 @@ extern int memory_isolate_notify(unsigne extern struct memory_block *find_memory_block_hinted(struct mem_section *, struct memory_block *); extern struct memory_block *find_memory_block(struct mem_section *); +extern bool is_memblk_offline(unsigned long start, unsigned long size); #define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<