1 files changed, 44 insertions, 27 deletions

diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 7602c001e92b..7e8dc648b95a 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -74,11 +74,23 @@ static void _batadv_update_route(struct batadv_priv *bat_priv,
 	if (!orig_ifinfo)
 		return;
 
-	rcu_read_lock();
-	curr_router = rcu_dereference(orig_ifinfo->router);
-	if (curr_router && !kref_get_unless_zero(&curr_router->refcount))
-		curr_router = NULL;
-	rcu_read_unlock();
+	spin_lock_bh(&orig_node->neigh_list_lock);
+	/* curr_router used earlier may not be the current orig_ifinfo->router
+	 * anymore because it was dereferenced outside of the neigh_list_lock
+	 * protected region. After the new best neighbor has replace the current
+	 * best neighbor the reference counter needs to decrease. Consequently,
+	 * the code needs to ensure the curr_router variable contains a pointer
+	 * to the replaced best neighbor.
+	 */
+	curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
+
+	/* increase refcount of new best neighbor */
+	if (neigh_node)
+		kref_get(&neigh_node->refcount);
+
+	rcu_assign_pointer(orig_ifinfo->router, neigh_node);
+	spin_unlock_bh(&orig_node->neigh_list_lock);
+	batadv_orig_ifinfo_put(orig_ifinfo);
 
 	/* route deleted */
 	if ((curr_router) && (!neigh_node)) {
@@ -100,27 +112,6 @@ static void _batadv_update_route(struct batadv_priv *bat_priv,
 			   curr_router->addr);
 	}
 
-	if (curr_router)
-		batadv_neigh_node_put(curr_router);
-
-	spin_lock_bh(&orig_node->neigh_list_lock);
-	/* curr_router used earlier may not be the current orig_ifinfo->router
-	 * anymore because it was dereferenced outside of the neigh_list_lock
-	 * protected region. After the new best neighbor has replace the current
-	 * best neighbor the reference counter needs to decrease. Consequently,
-	 * the code needs to ensure the curr_router variable contains a pointer
-	 * to the replaced best neighbor.
-	 */
-	curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
-
-	/* increase refcount of new best neighbor */
-	if (neigh_node)
-		kref_get(&neigh_node->refcount);
-
-	rcu_assign_pointer(orig_ifinfo->router, neigh_node);
-	spin_unlock_bh(&orig_node->neigh_list_lock);
-	batadv_orig_ifinfo_put(orig_ifinfo);
-
 	/* decrease refcount of previous best neighbor */
 	if (curr_router)
 		batadv_neigh_node_put(curr_router);
@@ -470,6 +461,29 @@ static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 }
 
 /**
+ * batadv_last_bonding_get - Get last_bonding_candidate of orig_node
+ * @orig_node: originator node whose last bonding candidate should be retrieved
+ *
+ * Return: last bonding candidate of router or NULL if not found
+ *
+ * The object is returned with refcounter increased by 1.
+ */
+static struct batadv_orig_ifinfo *
+batadv_last_bonding_get(struct batadv_orig_node *orig_node)
+{
+	struct batadv_orig_ifinfo *last_bonding_candidate;
+
+	spin_lock_bh(&orig_node->neigh_list_lock);
+	last_bonding_candidate = orig_node->last_bonding_candidate;
+
+	if (last_bonding_candidate)
+		kref_get(&last_bonding_candidate->refcount);
+	spin_unlock_bh(&orig_node->neigh_list_lock);
+
+	return last_bonding_candidate;
+}
+
+/**
  * batadv_last_bonding_replace - Replace last_bonding_candidate of orig_node
  * @orig_node: originator node whose bonding candidates should be replaced
  * @new_candidate: new bonding candidate or NULL
@@ -539,7 +553,7 @@ batadv_find_router(struct batadv_priv *bat_priv,
 	 * router - obviously there are no other candidates.
 	 */
 	rcu_read_lock();
-	last_candidate = orig_node->last_bonding_candidate;
+	last_candidate = batadv_last_bonding_get(orig_node);
 	if (last_candidate)
 		last_cand_router = rcu_dereference(last_candidate->router);
 
@@ -631,6 +645,9 @@ next:
 		batadv_orig_ifinfo_put(next_candidate);
 	}
 
+	if (last_candidate)
+		batadv_orig_ifinfo_put(last_candidate);
+
 	return router;
 }