ACPI: scan: Introduce acpi_fetch_acpi_dev()

Introduce acpi_fetch_acpi_dev() as a more reasonable replacement for
acpi_bus_get_device() and modify the code in scan.c to use it instead
of the latter.

No expected functional impact.

Signed-off-by: Rafael J. Wysocki <[e-mail]>
Reviewed-by: Mika Westerberg <[e-mail]>
Reviewed-by: Hans de Goede <[e-mail]>

drivers/acpi/scan.c

···
 static acpi_status acpi_bus_offline(acpi_handle handle, u32 lvl, void *data,
 				    void **ret_p)
 {
-	struct acpi_device *device = NULL;
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 	struct acpi_device_physical_node *pn;
 	bool second_pass = (bool)data;
 	acpi_status status = AE_OK;
 
-	if (acpi_bus_get_device(handle, &device))
+	if (!device)
 		return AE_OK;
 
 	if (device->handler && !device->handler->hotplug.enabled) {
···
 static acpi_status acpi_bus_online(acpi_handle handle, u32 lvl, void *data,
 				   void **ret_p)
 {
-	struct acpi_device *device = NULL;
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 	struct acpi_device_physical_node *pn;
 
-	if (acpi_bus_get_device(handle, &device))
+	if (!device)
 		return AE_OK;
 
 	mutex_lock(&device->physical_node_lock);
···
 }
 EXPORT_SYMBOL(acpi_bus_get_device);
 
+/**
+ * acpi_fetch_acpi_dev - Retrieve ACPI device object.
+ * @handle: ACPI handle associated with the requested ACPI device object.
+ *
+ * Return a pointer to the ACPI device object associated with @handle, if
+ * present, or NULL otherwise.
+ */
+struct acpi_device *acpi_fetch_acpi_dev(acpi_handle handle)
+{
+	return handle_to_device(handle, NULL);
+}
+EXPORT_SYMBOL_GPL(acpi_fetch_acpi_dev);
+
 static void get_acpi_device(void *dev)
 {
 	acpi_dev_get(dev);
···
 
 static struct acpi_device *acpi_bus_get_parent(acpi_handle handle)
 {
-	struct acpi_device *device = NULL;
+	struct acpi_device *device;
 	acpi_status status;
 
 	/*
···
 		status = acpi_get_parent(handle, &handle);
 		if (ACPI_FAILURE(status))
 			return status == AE_NULL_ENTRY ? NULL : acpi_root;
-	} while (acpi_bus_get_device(handle, &device));
+
+		device = acpi_fetch_acpi_dev(handle);
+	} while (!device);
 	return device;
 }
 
···
 static acpi_status acpi_bus_check_add(acpi_handle handle, bool check_dep,
 				      struct acpi_device **adev_p)
 {
-	struct acpi_device *device = NULL;
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 	acpi_object_type acpi_type;
 	int type;
 
-	acpi_bus_get_device(handle, &device);
 	if (device)
 		goto out;
 
···
 	if (result)
 		goto out;
 
-	result = acpi_bus_get_device(ACPI_ROOT_OBJECT, &acpi_root);
-	if (result)
+	acpi_root = acpi_fetch_acpi_dev(ACPI_ROOT_OBJECT);
+	if (!acpi_root)
 		goto out;
 
 	/* Fixed feature devices do not exist on HW-reduced platform */

include/acpi/acpi_bus.h

···
  */
 
 int acpi_bus_get_device(acpi_handle handle, struct acpi_device **device);
+struct acpi_device *acpi_fetch_acpi_dev(acpi_handle handle);
 acpi_status acpi_bus_get_status_handle(acpi_handle handle,
 				       unsigned long long *sta);
 int acpi_bus_get_status(struct acpi_device *device);