batman-adv: invoke dev_get_by_index() outside of is_wifi_iface()

Upcoming changes need to perform other checks on the
incoming net_device struct.

To avoid performing dev_get_by_index() for each and every
check, it is better to move it outside of is_wifi_iface()
and search the netdev object once only.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index a3c965d..b0fe177 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -477,11 +477,15 @@
 	struct batadv_priv *bat_priv = netdev_priv(soft_iface);
 	struct batadv_tt_local_entry *tt_local;
 	struct batadv_tt_global_entry *tt_global;
+	struct net_device *in_dev = NULL;
 	struct hlist_head *head;
 	struct batadv_tt_orig_list_entry *orig_entry;
 	int hash_added, table_size, packet_size_max;
 	bool ret = false, roamed_back = false;
 
+	if (ifindex != BATADV_NULL_IFINDEX)
+		in_dev = dev_get_by_index(&init_net, ifindex);
+
 	tt_local = batadv_tt_local_hash_find(bat_priv, addr, vid);
 	tt_global = batadv_tt_global_hash_find(bat_priv, addr, vid);
 
@@ -542,7 +546,7 @@
 	 */
 	tt_local->common.flags = BATADV_TT_CLIENT_NEW;
 	tt_local->common.vid = vid;
-	if (batadv_is_wifi_iface(ifindex))
+	if (batadv_is_wifi_netdev(in_dev))
 		tt_local->common.flags |= BATADV_TT_CLIENT_WIFI;
 	atomic_set(&tt_local->common.refcount, 2);
 	tt_local->last_seen = jiffies;
@@ -595,6 +599,8 @@
 	ret = true;
 
 out:
+	if (in_dev)
+		dev_put(in_dev);
 	if (tt_local)
 		batadv_tt_local_entry_free_ref(tt_local);
 	if (tt_global)