From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx172.postini.com [74.125.245.172]) by kanga.kvack.org (Postfix) with SMTP id 721D66B005A for ; Thu, 29 Nov 2012 08:15:45 -0500 (EST) Received: by mail-ie0-f169.google.com with SMTP id c14so10248156ieb.14 for ; Thu, 29 Nov 2012 05:15:44 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1352962777-24407-6-git-send-email-wency@cn.fujitsu.com> References: <1352962777-24407-1-git-send-email-wency@cn.fujitsu.com> <1352962777-24407-6-git-send-email-wency@cn.fujitsu.com> Date: Thu, 29 Nov 2012 21:15:44 +0800 Message-ID: Subject: Re: [Patch v5 5/7] acpi_memhotplug.c: don't allow to eject the memory device if it is being used From: =?GB2312?B?YW5keXd1MTA2vai5+g==?= Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Wen Congyang Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-acpi@vger.kernel.org, Len Brown , "Rafael J. Wysocki" , Andrew Morton , Yasuaki Ishimatsu , Lai Jiangshan , Jiang Liu , KOSAKI Motohiro , Minchan Kim , Mel Gorman , David Rientjes , Konrad Rzeszutek Wilk , Toshi Kani , Jiang Liu , Benjamin Herrenschmidt , Paul Mackerras , Christoph Lameter 2012/11/15 Wen Congyang > > 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 | 42 +++++++++++++++++++++++++++++++++--------- > 1 file changed, 33 insertions(+), 9 deletions(-) > > diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c > index e52ad5d..f7e3007 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 { > @@ -257,9 +258,23 @@ 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; Hi Congyang, If a memory device booting with the system, the info->enable will equal to 0, and can not be hot-removed in acpi_memory_remove_memory(), right? Thanks, Jianguo Wu > > + /* > + * Add num_enable even if add_memory() returns -EEXIST, so the > + * device is bound to this driver. > + */ > num_enabled++; > } > if (!num_enabled) { > @@ -280,21 +295,30 @@ static int acpi_memory_enable_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; > > 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) > - 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. > + */ > + return -EBUSY; > + > + result = remove_memory(info->start_addr, info->length); > + if (result) > + return result; > > list_del(&info->list); > kfree(info); > } > > - return 0; > + return result; > } > > static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data) > -- > 1.8.0 > > -- > 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 -- 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