serdev: fix controller-allocation error handling

Reorder controller initialisation so that in the unlikely event that id
allocation fails, we don't end up releasing id 0 in the destructor.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serdev/core.c

@@ -358,26 +358,31 @@ struct serdev_controller *serdev_controller_alloc(struct device *parent,
 	if (!ctrl)
 		return NULL;
 
-	device_initialize(&ctrl->dev);
-	ctrl->dev.type = &serdev_ctrl_type;
-	ctrl->dev.bus = &serdev_bus_type;
-	ctrl->dev.parent = parent;
-	ctrl->dev.of_node = parent->of_node;
-	serdev_controller_set_drvdata(ctrl, &ctrl[1]);
-
 	id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
 	if (id < 0) {
 		dev_err(parent,
 			"unable to allocate serdev controller identifier.\n");
-		serdev_controller_put(ctrl);
-		return NULL;
+		goto err_free;
 	}
 
 	ctrl->nr = id;
+
+	device_initialize(&ctrl->dev);
+	ctrl->dev.type = &serdev_ctrl_type;
+	ctrl->dev.bus = &serdev_bus_type;
+	ctrl->dev.parent = parent;
+	ctrl->dev.of_node = parent->of_node;
+	serdev_controller_set_drvdata(ctrl, &ctrl[1]);
+
 	dev_set_name(&ctrl->dev, "serial%d", id);
 
 	dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
 	return ctrl;
+
+err_free:
+	kfree(ctrl);
+
+	return NULL;
 }
 EXPORT_SYMBOL_GPL(serdev_controller_alloc);