batman-adv: Place kref_get for tvlv_handler near use

It is hard to understand why the refcnt is increased when it isn't done
near the actual place the new reference is used. So using kref_get right
before the place which requires the reference and in the same function
helps to avoid accidental problems caused by incorrect reference counting.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

net/batman-adv/tvlv.c

@@ -547,8 +547,12 @@ void batadv_tvlv_handler_register(struct batadv_priv *bat_priv,
 	INIT_HLIST_NODE(&tvlv_handler->list);
 
 	spin_lock_bh(&bat_priv->tvlv.handler_list_lock);
+	kref_get(&tvlv_handler->refcount);
 	hlist_add_head_rcu(&tvlv_handler->list, &bat_priv->tvlv.handler_list);
 	spin_unlock_bh(&bat_priv->tvlv.handler_list_lock);
+
+	/* don't return reference to new tvlv_handler */
+	batadv_tvlv_handler_put(tvlv_handler);
 }
 
 /**