Patchwork [RFC,v4,12/13] memory-hotplug : add node_device_release

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Submitter Yasuaki Ishimatsu
Date July 18, 2012, 10:17 a.m.
Message ID <50068D41.9090109@jp.fujitsu.com>
Download mbox | patch
Permalink /patch/171637/
State Not Applicable
Headers show

Comments

Yasuaki Ishimatsu - July 18, 2012, 10:17 a.m.
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.

So the patch implements node_device_release()

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org> 
CC: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> 
CC: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

---
 drivers/base/node.c |    7 +++++++
 1 file changed, 7 insertions(+)
Wen Congyang - July 27, 2012, 6:17 a.m.
At 07/18/2012 06:17 PM, 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.
> 
> So the patch implements node_device_release()
> 
> CC: David Rientjes <rientjes@google.com>
> CC: Jiang Liu <liuj97@gmail.com>
> CC: Len Brown <len.brown@intel.com>
> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> CC: Paul Mackerras <paulus@samba.org> 
> CC: Christoph Lameter <cl@linux.com>
> Cc: Minchan Kim <minchan.kim@gmail.com>
> CC: Andrew Morton <akpm@linux-foundation.org>
> CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> 
> CC: Wen Congyang <wency@cn.fujitsu.com>
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> 
> ---
>  drivers/base/node.c |    7 +++++++
>  1 file changed, 7 insertions(+)
> 
> Index: linux-3.5-rc6/drivers/base/node.c
> ===================================================================
> --- linux-3.5-rc6.orig/drivers/base/node.c	2012-07-18 18:24:29.191121066 +0900
> +++ linux-3.5-rc6/drivers/base/node.c	2012-07-18 18:25:47.111146983 +0900
> @@ -252,6 +252,12 @@ static inline void hugetlb_register_node
>  static inline void hugetlb_unregister_node(struct node *node) {}
>  #endif
>  
> +static void node_device_release(struct device *dev)
> +{
> +	struct node *node_dev = to_node(dev);
> +
> +	memset(node_dev, 0, sizeof(struct node));

This line is wrong. node_dev->work_struct may be queued in workqueue.
So, it is very dangerous to clear node_dev->work_struct here.
In my test, it will cause kernel panicked.

Thanks
Wen Congyang
> +}
>  
>  /*
>   * register_node - Setup a sysfs device for a node.
> @@ -265,6 +271,7 @@ int register_node(struct node *node, int
>  
>  	node->dev.id = num;
>  	node->dev.bus = &node_subsys;
> +	node->dev.release = node_device_release;
>  	error = device_register(&node->dev);
>  
>  	if (!error){
> 
> --
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Patch

Index: linux-3.5-rc6/drivers/base/node.c
===================================================================
--- linux-3.5-rc6.orig/drivers/base/node.c	2012-07-18 18:24:29.191121066 +0900
+++ linux-3.5-rc6/drivers/base/node.c	2012-07-18 18:25:47.111146983 +0900
@@ -252,6 +252,12 @@  static inline void hugetlb_register_node
 static inline void hugetlb_unregister_node(struct node *node) {}
 #endif
 
+static void node_device_release(struct device *dev)
+{
+	struct node *node_dev = to_node(dev);
+
+	memset(node_dev, 0, sizeof(struct node));
+}
 
 /*
  * register_node - Setup a sysfs device for a node.
@@ -265,6 +271,7 @@  int register_node(struct node *node, int
 
 	node->dev.id = num;
 	node->dev.bus = &node_subsys;
+	node->dev.release = node_device_release;
 	error = device_register(&node->dev);
 
 	if (!error){