Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755637Ab2JQGSe (ORCPT ); Wed, 17 Oct 2012 02:18:34 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:47559 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754314Ab2JQGSd (ORCPT ); Wed, 17 Oct 2012 02:18:33 -0400 X-IronPort-AV: E=Sophos;i="4.80,598,1344182400"; d="scan'208";a="6013990" Message-ID: <507E4F0C.9040506@cn.fujitsu.com> Date: Wed, 17 Oct 2012 14:24:12 +0800 From: Wen Congyang User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100413 Fedora/3.0.4-2.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 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 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: X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/17 14:18:11, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/17 14:18:12, Serialize complete at 2012/10/17 14:18:12 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2709 Lines: 73 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 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/