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: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/vmlogrdr.c

@@ -668,6 +668,13 @@ static struct attribute *vmlogrdr_attrs[] = {
 	&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)
 {
@@ -692,10 +699,6 @@ 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;
 static struct device_driver vmlogrdr_driver = {
 	.name = "vmlogrdr",
@@ -762,6 +765,7 @@ static int vmlogrdr_register_device(struct vmlogrdr_priv_t *priv)
 		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
@@ -779,11 +783,6 @@ static int vmlogrdr_register_device(struct vmlogrdr_priv_t *priv)
 		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),
@@ -791,7 +790,6 @@ static int vmlogrdr_register_device(struct vmlogrdr_priv_t *priv)
 	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;
 	}
@@ -804,7 +802,6 @@ static int vmlogrdr_unregister_device(struct vmlogrdr_priv_t *priv)
 {
 	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;
 	}