ACPI / memory-hotplug: add memory offline code to acpi_memory_device_remove()

The memory device can be removed by 2 ways:
 1. send eject request by SCI
 2. echo 1 >/sys/bus/pci/devices/PNP0C80:XX/eject

In the 1st case, acpi_memory_disable_device() will be called.
In the 2nd case, acpi_memory_device_remove() will be called.
acpi_memory_device_remove() will also be called when we unbind the
memory device from the driver acpi_memhotplug or a driver initialization
fails.

acpi_memory_disable_device() has already implemented a code which
offlines memory and releases acpi_memory_info struct. But
acpi_memory_device_remove() has not implemented it yet.

So the patch move offlining memory and releasing acpi_memory_info struct
codes to a new function acpi_memory_remove_memory(). And it is used by both
acpi_memory_device_remove() and acpi_memory_disable_device().

Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.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

@@ -306,25 +306,37 @@ static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
 	return 0;
 }
 
-static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
+static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
 {
 	int result;
 	struct acpi_memory_info *info, *n;
 
-
-	/*
-	 * Ask the VM to offline this memory range.
-	 * Note: Assume that this function returns zero on success
-	 */
 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 		if (info->enabled) {
 			result = remove_memory(info->start_addr, info->length);
 			if (result)
 				return result;
 		}
+
+		list_del(&info->list);
 		kfree(info);
 	}
 
+	return 0;
+}
+
+static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
+{
+	int result;
+
+	/*
+	 * Ask the VM to offline this memory range.
+	 * Note: Assume that this function returns zero on success
+	 */
+	result = acpi_memory_remove_memory(mem_device);
+	if (result)
+		return result;
+
 	/* Power-off and eject the device */
 	result = acpi_memory_powerdown_device(mem_device);
 	if (result) {
@@ -474,12 +486,17 @@ static int acpi_memory_device_add(struct acpi_device *device)
 static int acpi_memory_device_remove(struct acpi_device *device, int type)
 {
 	struct acpi_memory_device *mem_device = NULL;
-
+	int result;
 
 	if (!device || !acpi_driver_data(device))
 		return -EINVAL;
 
 	mem_device = acpi_driver_data(device);
+
+	result = acpi_memory_remove_memory(mem_device);
+	if (result)
+		return result;
+
 	kfree(mem_device);
 
 	return 0;