ACPI / memhotplug: fix memory leak when memory device is unbound from acpi_memhotplug

We allocate memory to store acpi_memory_info, so we should free it before
freeing mem_device.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpi_memhotplug.c

@@ -125,12 +125,20 @@ acpi_memory_get_resource(struct acpi_resource *resource, void *context)
 	return AE_OK;
 }
 
+static void
+acpi_memory_free_device_resources(struct acpi_memory_device *mem_device)
+{
+	struct acpi_memory_info *info, *n;
+
+	list_for_each_entry_safe(info, n, &mem_device->res_list, list)
+		kfree(info);
+	INIT_LIST_HEAD(&mem_device->res_list);
+}
+
 static int
 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
 {
 	acpi_status status;
-	struct acpi_memory_info *info, *n;
-
 
 	if (!list_empty(&mem_device->res_list))
 		return 0;
@@ -138,9 +146,7 @@ acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
 	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);
+		acpi_memory_free_device_resources(mem_device);
 		return -EINVAL;
 	}
 
@@ -363,6 +369,15 @@ static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
 	return;
 }
 
+static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
+{
+	if (!mem_device)
+		return;
+
+	acpi_memory_free_device_resources(mem_device);
+	kfree(mem_device);
+}
+
 static int acpi_memory_device_add(struct acpi_device *device)
 {
 	int result;
@@ -427,7 +442,7 @@ static int acpi_memory_device_remove(struct acpi_device *device, int type)
 	if (result)
 		return result;
 
-	kfree(mem_device);
+	acpi_memory_device_free(mem_device);
 
 	return 0;
 }