batman-adv: Clean up untagged vlan when destroying via rtnl-link

BugLink: https://bugs.launchpad.net/bugs/1868629

commit 420cb1b7 upstream.

The untagged vlan object is only destroyed when the interface is removed
via the legacy sysfs interface. But it also has to be destroyed when the
standard rtnl-link interface is used.

Fixes: 5d2c05b2 ("batman-adv: add per VLAN interface attribute framework")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Acked-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

net/batman-adv/soft-interface.c

@@ -1000,7 +1000,9 @@ void batadv_softif_destroy_sysfs(struct net_device *soft_iface)
 static void batadv_softif_destroy_netlink(struct net_device *soft_iface,
 					  struct list_head *head)
 {
+	struct batadv_priv *bat_priv = netdev_priv(soft_iface);
 	struct batadv_hard_iface *hard_iface;
+	struct batadv_softif_vlan *vlan;
 
 	list_for_each_entry(hard_iface, &batadv_hardif_list, list) {
 		if (hard_iface->soft_iface == soft_iface)
@@ -1008,6 +1010,13 @@ static void batadv_softif_destroy_netlink(struct net_device *soft_iface,
 							BATADV_IF_CLEANUP_KEEP);
 	}
 
+	/* destroy the "untagged" VLAN */
+	vlan = batadv_softif_vlan_get(bat_priv, BATADV_NO_FLAGS);
+	if (vlan) {
+		batadv_softif_destroy_vlan(bat_priv, vlan);
+		batadv_softif_vlan_free_ref(vlan);
+	}
+
 	batadv_sysfs_del_meshif(soft_iface);
 	unregister_netdevice_queue(soft_iface, head);
 }