s390/vmlogrdr: cleanup device attribute usage

Let the driver core handle device attribute creation and removal. This
will simplify the code and eliminates races between attribute
availability and userspace notification via uevents.

Signed-off-by: Sebastian Ott <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

drivers/s390/char/vmlogrdr.c

···
 	&dev_attr_recording.attr,
 	NULL,
 };
+static struct attribute_group vmlogrdr_attr_group = {
+	.attrs = vmlogrdr_attrs,
+};
+static const struct attribute_group *vmlogrdr_attr_groups[] = {
+	&vmlogrdr_attr_group,
+	NULL,
+};
 
 static int vmlogrdr_pm_prepare(struct device *dev)
 {
···
 
 static const struct dev_pm_ops vmlogrdr_pm_ops = {
 	.prepare = vmlogrdr_pm_prepare,
-};
-
-static struct attribute_group vmlogrdr_attr_group = {
-	.attrs = vmlogrdr_attrs,
 };
 
 static struct class *vmlogrdr_class;
···
 		dev->bus = &iucv_bus;
 		dev->parent = iucv_root;
 		dev->driver = &vmlogrdr_driver;
+		dev->groups = vmlogrdr_attr_groups;
 		dev_set_drvdata(dev, priv);
 		/*
 		 * The release function could be called after the
···
 		return ret;
 	}
 
-	ret = sysfs_create_group(&dev->kobj, &vmlogrdr_attr_group);
-	if (ret) {
-		device_unregister(dev);
-		return ret;
-	}
 	priv->class_device = device_create(vmlogrdr_class, dev,
 					   MKDEV(vmlogrdr_major,
 						 priv->minor_num),
···
 	if (IS_ERR(priv->class_device)) {
 		ret = PTR_ERR(priv->class_device);
 		priv->class_device=NULL;
-		sysfs_remove_group(&dev->kobj, &vmlogrdr_attr_group);
 		device_unregister(dev);
 		return ret;
 	}
···
 {
 	device_destroy(vmlogrdr_class, MKDEV(vmlogrdr_major, priv->minor_num));
 	if (priv->device != NULL) {
-		sysfs_remove_group(&priv->device->kobj, &vmlogrdr_attr_group);
 		device_unregister(priv->device);
 		priv->device=NULL;
 	}