From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

both of acpi_memory_enable_device() and acpi_memory_add_device() may evaluate
_CRS method.

We should avoid evaluate device's resource twice if we could get it
successfully in past.

Signed-off-by: KAMEZWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Keith Mannthey <kmannth@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 drivers/acpi/acpi_memhotplug.c |    4 ++++
 1 file changed, 4 insertions(+)

diff -puN drivers/acpi/acpi_memhotplug.c~memory-hotadd-fixes-avoid-registering-res-twice drivers/acpi/acpi_memhotplug.c
--- a/drivers/acpi/acpi_memhotplug.c~memory-hotadd-fixes-avoid-registering-res-twice
+++ a/drivers/acpi/acpi_memhotplug.c
@@ -129,11 +129,15 @@ acpi_memory_get_device_resources(struct 
 	struct acpi_memory_info *info, *n;
 
 
+	if (!list_empty(&mem_device->res_list))
+		return 0;
+
 	status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
 				     acpi_memory_get_resource, mem_device);
 	if (ACPI_FAILURE(status)) {
 		list_for_each_entry_safe(info, n, &mem_device->res_list, list)
 			kfree(info);
+		INIT_LIST_HEAD(&mem_device->res_list);
 		return -EINVAL;
 	}
 
_