batman-adv: Use kref_get for batadv_gw_node_add

batadv_gw_node_add requires that the caller already has a valid reference
for orig_node. It is therefore not possible that it has an reference
counter of 0 and was still given to this function

The kref_get function instead WARNs (with debug information) when the
reference counter would still be 0. This makes a bug in batman-adv better
visible because kref_get_unless_zero would have ignored this problem.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>

diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
index bb1c4f3..5839c56 100644 (file)
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -440,15 +440,11 @@ static void batadv_gw_node_add(struct batadv_priv *bat_priv,
        if (gateway->bandwidth_down == 0)
                return;
 
-       if (!kref_get_unless_zero(&orig_node->refcount))
-               return;
-
        gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
-       if (!gw_node) {
-               batadv_orig_node_put(orig_node);
+       if (!gw_node)
                return;
-       }
 
+       kref_get(&orig_node->refcount);
        INIT_HLIST_NODE(&gw_node->list);
        gw_node->orig_node = orig_node;
        gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);