Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755399Ab2KHK7e (ORCPT ); Thu, 8 Nov 2012 05:59:34 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:55618 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753889Ab2KHK7E (ORCPT ); Thu, 8 Nov 2012 05:59:04 -0500 X-IronPort-AV: E=Sophos;i="4.80,737,1344182400"; d="scan'208";a="6161806" From: Wen Congyang To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-acpi@vger.kernel.org, Len Brown Cc: "Rafael J. Wysocki" , Andrew Morton , Yasuaki Ishimatsu , Lai Jiangshan , Jiang Liu , KOSAKI Motohiro , Minchan Kim , Mel Gorman , David Rientjes , Konrad Rzeszutek Wilk , Toshi Kani , Wen Congyang , Jiang Liu , Benjamin Herrenschmidt , Paul Mackerras , Christoph Lameter Subject: [Patch v4 5/7] acpi_memhotplug.c: don't allow to eject the memory device if it is being used Date: Thu, 8 Nov 2012 19:04:51 +0800 Message-Id: <1352372693-32411-6-git-send-email-wency@cn.fujitsu.com> X-Mailer: git-send-email 1.8.0 In-Reply-To: <1352372693-32411-1-git-send-email-wency@cn.fujitsu.com> References: <1352372693-32411-1-git-send-email-wency@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/08 18:58:59, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/08 18:59:02, Serialize complete at 2012/11/08 18:59:02 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3360 Lines: 111 We eject the memory device even if it is in use. It is very dangerous, and it will cause the kernel to be panicked. CC: David Rientjes CC: Jiang Liu CC: Len Brown CC: Benjamin Herrenschmidt CC: Paul Mackerras CC: Christoph Lameter Cc: Minchan Kim CC: Andrew Morton CC: KOSAKI Motohiro CC: Yasuaki Ishimatsu CC: Rafael J. Wysocki CC: Konrad Rzeszutek Wilk Signed-off-by: Wen Congyang --- drivers/acpi/acpi_memhotplug.c | 46 +++++++++++++++++++++++++++++++++--------- 1 file changed, 36 insertions(+), 10 deletions(-) diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c index 8914399..1fb1342 100644 --- a/drivers/acpi/acpi_memhotplug.c +++ b/drivers/acpi/acpi_memhotplug.c @@ -78,6 +78,7 @@ struct acpi_memory_info { unsigned short caching; /* memory cache attribute */ unsigned short write_protect; /* memory read/write attribute */ unsigned int enabled:1; + unsigned int failed:1; }; struct acpi_memory_device { @@ -266,9 +267,23 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device) node = memory_add_physaddr_to_nid(info->start_addr); result = add_memory(node, info->start_addr, info->length); - if (result) + + /* + * If the memory block has been used by the kernel, add_memory() + * returns -EEXIST. If add_memory() returns the other error, it + * means that this memory block is not used by the kernel. + */ + if (result && result != -EEXIST) { + info->failed = 1; continue; - info->enabled = 1; + } + + if (!result) + info->enabled = 1; + /* + * Add num_enable even if add_memory() returns -EEXIST, so the + * device is bound to this driver. + */ num_enabled++; } mutex_unlock(&mem_device->list_lock); @@ -324,25 +339,36 @@ static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device) static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device) { - int result; + int result = 0; struct acpi_memory_info *info, *n; mutex_lock(&mem_device->list_lock); list_for_each_entry_safe(info, n, &mem_device->res_list, list) { - if (info->enabled) { - result = remove_memory(info->start_addr, info->length); - if (result) { - mutex_unlock(&mem_device->list_lock); - return result; - } + if (info->failed) + /* The kernel does not use this memory block */ + continue; + + if (!info->enabled) { + /* + * The kernel uses this memory block, but it may be not + * managed by us. + */ + result = -EBUSY; + goto out; } + result = remove_memory(info->start_addr, info->length); + if (result) + goto out; + list_del(&info->list); kfree(info); } + +out: mutex_unlock(&mem_device->list_lock); - return 0; + return result; } static int acpi_memory_disable_device(struct acpi_memory_device *mem_device) -- 1.8.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/