tun: Use static attribute groups for sysfs entries

Instead of manual calls of device_create_file() and
device_remove_files(), assign the static attribute groups to netdev
groups array.  This simplifies the code and avoids the possible
races.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/tun.c

@@ -1565,6 +1565,17 @@ static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
 
+static struct attribute *tun_dev_attrs[] = {
+	&dev_attr_tun_flags.attr,
+	&dev_attr_owner.attr,
+	&dev_attr_group.attr,
+	NULL
+};
+
+static const struct attribute_group tun_attr_group = {
+	.attrs = tun_dev_attrs
+};
+
 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 {
 	struct tun_struct *tun;
@@ -1645,6 +1656,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 		dev_net_set(dev, net);
 		dev->rtnl_link_ops = &tun_link_ops;
 		dev->ifindex = tfile->ifindex;
+		dev->sysfs_groups[0] = &tun_attr_group;
 
 		tun = netdev_priv(dev);
 		tun->dev = dev;
@@ -1680,11 +1692,6 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 		err = register_netdevice(tun->dev);
 		if (err < 0)
 			goto err_detach;
-
-		if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
-		    device_create_file(&tun->dev->dev, &dev_attr_owner) ||
-		    device_create_file(&tun->dev->dev, &dev_attr_group))
-			pr_err("Failed to create tun sysfs files\n");
 	}
 
 	netif_carrier_on(tun->dev);