# \[Patch v4 06/12\] memory-hotplug: unregister memory section on SPARSEMEM\_VMEMMAP

- From: Wen Congyang \<hidden\>
- Date: 2012-11-27 09:58:25 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2012/11/3963800
- Thread: https://ratatoskr.run/linux-mm/2012/11/3963802/t.md

```text
From: Yasuaki Ishimatsu <redacted>

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 <rientjes@google.com>
CC: Jiang Liu <redacted>
CC: Len Brown <redacted>
CC: Christoph Lameter <redacted>
Cc: Minchan Kim <redacted>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <redacted>
Signed-off-by: Yasuaki Ishimatsu <redacted>
Signed-off-by: Wen Congyang <redacted>
---
 mm/memory_hotplug.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e741732..171610d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -279,11 +279,14 @@ static int __meminit __add_section(int nid, struct zone *zone,
 #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)
-- 
1.8.0
```