batman-adv: Increase hard_iface refcnt for ptype

The hard_iface is referenced in the packet_type for batman-adv. Increase
the refcounter of the hard_interface for it to have an explicit reference
for it in case this functionality gets refactorted and the currently
used implicit reference for it will be removed.
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

@@ -522,6 +522,7 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
 		goto err_upper;
 	}
 
+	kref_get(&hard_iface->refcount);
 	hard_iface->batman_adv_ptype.type = ethertype;
 	hard_iface->batman_adv_ptype.func = batadv_batman_skb_recv;
 	hard_iface->batman_adv_ptype.dev = hard_iface->net_dev;
@@ -583,6 +584,7 @@ void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface,
 	batadv_info(hard_iface->soft_iface, "Removing interface: %s\n",
 		    hard_iface->net_dev->name);
 	dev_remove_pack(&hard_iface->batman_adv_ptype);
+	batadv_hardif_put(hard_iface);
 
 	bat_priv->num_ifaces--;
 	batadv_orig_hash_del_if(hard_iface, bat_priv->num_ifaces);