Subject: [PATCH 4/10] memory-hotplug : unregister memory section on SPARSEMEM_VMEMMAP

From: Yasuaki Ishimatsu <[email-masked]>
Date: Fri, 5 Oct 2012 11:31:07 +0900

Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But even if
we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.

So the patch add unregister_memory_section() into __remove_section().

CC: David Rientjes <[email-masked]>
CC: Jiang Liu <[email-masked]>
CC: Len Brown <[email-masked]>
CC: Christoph Lameter <[email-masked]>
Cc: Minchan Kim <[email-masked]>
CC: Andrew Morton <[email-masked]>
CC: KOSAKI Motohiro <[email-masked]> 
CC: Wen Congyang <[email-masked]>
Signed-off-by: Yasuaki Ishimatsu <[email-masked]>
---
 mm/memory_hotplug.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

Index: linux-3.6/mm/memory_hotplug.c
===================================================================
--- linux-3.6.orig/mm/memory_hotplug.c	2012-10-04 18:29:50.577668254 +0900
+++ linux-3.6/mm/memory_hotplug.c	2012-10-04 18:29:58.284676075 +0900
@@ -279,11 +279,14 @@ static int __meminit __add_section(int n
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 static int __remove_section(struct zone *zone, struct mem_section *ms)
 {
-	/*
-	 * XXX: Freeing memmap with vmemmap is not implement yet.
-	 *      This should be removed later.
-	 */
-	return -EBUSY;
+	int ret = -EINVAL;
+
+	if (!valid_section(ms))
+		return ret;
+
+	ret = unregister_memory_section(ms);
+
+	return ret;
 }
 #else
 static int __remove_section(struct zone *zone, struct mem_section *ms)