[RFC PATCH 2/8] memory-hotplug: offline memory only when it is onlined

[Wen Congyang]

offline_memory() will fail if the memory is not onlined. So check
whether the memory is onlined before calling offline_memory().

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: Yasuaki Ishimatsu <isimatu.yasuaki at jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency at cn.fujitsu.com>
---
 drivers/acpi/acpi_memhotplug.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index db8de39..712e767 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -323,9 +323,13 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
 	 */
 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 		if (info->enabled) {
-			result = offline_memory(info->start_addr, info->length);
-			if (result)
-				return result;
+			if (!is_memblk_offline(info->start_addr,
+					       info->length)) {
+				result = offline_memory(info->start_addr,
+							info->length);
+				if (result)
+					return result;
+			}
 		}
 		list_del(&info->list);
 		kfree(info);
-- 
1.7.1