From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx133.postini.com [74.125.245.133]) by kanga.kvack.org (Postfix) with SMTP id 634D36B002B for ; Wed, 17 Oct 2012 02:18:34 -0400 (EDT) Message-ID: <507E4F0C.9040506@cn.fujitsu.com> Date: Wed, 17 Oct 2012 14:24:12 +0800 From: Wen Congyang MIME-Version: 1.0 Subject: Re: [PATCH 2/2]suppress "Device nodeX does not have a release() function" warning References: <507656D1.5020703@jp.fujitsu.com> <50765896.4000300@jp.fujitsu.com> In-Reply-To: Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: Yasuaki Ishimatsu , linux-mm@kvack.org, linux-kernel@vger.kernel.org, rientjes@google.com, liuj97@gmail.com, minchan.kim@gmail.com, akpm@linux-foundation.org At 10/12/2012 06:33 AM, KOSAKI Motohiro Wrote: > On Thu, Oct 11, 2012 at 1:26 AM, Yasuaki Ishimatsu > wrote: >> When calling unregister_node(), the function shows following message at >> device_release(). >> >> "Device 'node2' does not have a release() function, it is broken and must >> be fixed." >> >> The reason is node's device struct does not have a release() function. >> >> So the patch registers node_device_release() to the device's release() >> function for suppressing the warning message. Additionally, the patch adds >> memset() to initialize a node struct into register_node(). Because the node >> struct is part of node_devices[] array and it cannot be freed by >> node_device_release(). So if system reuses the node struct, it has a garbage. >> >> CC: David Rientjes >> CC: Jiang Liu >> Cc: Minchan Kim >> CC: Andrew Morton >> CC: KOSAKI Motohiro >> Signed-off-by: Yasuaki Ishimatsu >> Signed-off-by: Wen Congyang >> --- >> drivers/base/node.c | 11 +++++++++++ >> 1 file changed, 11 insertions(+) >> >> Index: linux-3.6/drivers/base/node.c >> =================================================================== >> --- linux-3.6.orig/drivers/base/node.c 2012-10-11 10:04:02.149758748 +0900 >> +++ linux-3.6/drivers/base/node.c 2012-10-11 10:20:34.111806931 +0900 >> @@ -252,6 +252,14 @@ static inline void hugetlb_register_node >> static inline void hugetlb_unregister_node(struct node *node) {} >> #endif >> >> +static void node_device_release(struct device *dev) >> +{ >> +#if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS) >> + struct node *node_dev = to_node(dev); >> + >> + flush_work(&node_dev->node_work); >> +#endif >> +} > > The patch description don't explain why this flush_work() is needed. If the node is onlined after it is offlined, we will clear the memory, so we should flush_work() before node_dev is set to 0. Thanks Wen Congyang > > >> /* >> * register_node - Setup a sysfs device for a node. >> @@ -263,8 +271,11 @@ int register_node(struct node *node, int >> { >> int error; >> >> + memset(node, 0, sizeof(*node)); >> + > > You should add a comment why we need initialize a node here. A lot > of developers don't have hotplug knowledge. > -- 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