[RFC PATCH v4 6/13] memory-hotplug : add memory_block_release

[Yasuaki Ishimatsu]

When calling remove_memory_block(), the function shows following message at
device_release().

Device 'memory528' does not have a release() function, it is broken and must
be fixed.

remove_memory_block() calls kfree(mem). I think it shouled be called from
device_release(). So the patch implements memory_block_release()

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

---
 drivers/base/memory.c |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

Index: linux-3.5-rc6/drivers/base/memory.c
===================================================================
--- linux-3.5-rc6.orig/drivers/base/memory.c	2012-07-18 17:50:49.659368740 +0900
+++ linux-3.5-rc6/drivers/base/memory.c	2012-07-18 17:51:28.655881214 +0900
@@ -109,6 +109,15 @@ bool is_memblk_offline(unsigned long sta
 }
 EXPORT_SYMBOL(is_memblk_offline);
 
+#define to_memory_block(device) container_of(device, struct memory_block, dev)
+
+static void release_memory_block(struct device *dev)
+{
+	struct memory_block *mem = to_memory_block(dev);
+
+	kfree(mem);
+}
+
 /*
  * register_memory - Setup a sysfs device for a memory block
  */
@@ -119,6 +128,7 @@ int register_memory(struct memory_block 
 
 	memory->dev.bus = &memory_subsys;
 	memory->dev.id = memory->start_section_nr / sections_per_block;
+	memory->dev.release = release_memory_block;
 
 	error = device_register(&memory->dev);
 	return error;
@@ -669,7 +679,6 @@ int remove_memory_block(unsigned long no
 		mem_remove_simple_file(mem, phys_device);
 		mem_remove_simple_file(mem, removable);
 		unregister_memory(mem);
-		kfree(mem);
 	} else
 		kobject_put(&mem->dev.kobj);