[PATCH] memory hotadd fixes: avoid registering res twice

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 <[e-mail]>
Cc: Keith Mannthey <[e-mail]>
Cc: Yasunori Goto <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/acpi/acpi_memhotplug.c

···
 	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;
 	}