batman-adv: Deactivate TO_BE_ACTIVATED hardif on shutdown

The shutdown of an batman-adv interface can happen with one of its slave
interfaces still being in the BATADV_IF_TO_BE_ACTIVATED state. A possible
reason for it is that the routing algorithm BATMAN_V was selected and
batadv_schedule_bat_ogm was not yet called for this interface. This slave
interface still has to be set to BATADV_IF_INACTIVE or the batman-adv
interface will never reduce its usage counter and thus never gets shutdown.

This problem can be simulated via:

    $ modprobe dummy
    $ modprobe batman-adv routing_algo=BATMAN_V
    $ ip link add bat0 type batadv
    $ ip link set dummy0 master bat0
    $ ip link set dummy0 up
    $ ip link del bat0
    unregister_netdevice: waiting for bat0 to become free. Usage count = 3

Reported-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>

net/batman-adv/hard-interface.c

@@ -572,8 +572,7 @@ void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface,
 	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 	struct batadv_hard_iface *primary_if = NULL;
 
-	if (hard_iface->if_status == BATADV_IF_ACTIVE)
-		batadv_hardif_deactivate_interface(hard_iface);
+	batadv_hardif_deactivate_interface(hard_iface);
 
 	if (hard_iface->if_status != BATADV_IF_INACTIVE)
 		goto out;