batman-adv: remove obsolete deleted attribute for gateway node

With rcu, the gateway node deleted attribute is not needed anymore. In
fact, it may delay the free of the gateway node and its referenced
structures. Therefore remove it altogether and simplify purging as well.

Signed-off-by: Simon Wunderlich <simon@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

net/batman-adv/gateway_client.c

@@ -161,9 +161,6 @@ batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
 
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
-		if (gw_node->deleted)
-			continue;
-
 		orig_node = gw_node->orig_node;
 		router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
 		if (!router)
@@ -473,9 +470,6 @@ batadv_gw_node_get(struct batadv_priv *bat_priv,
 		if (gw_node_tmp->orig_node != orig_node)
 			continue;
 
-		if (gw_node_tmp->deleted)
-			continue;
-
 		if (!atomic_inc_not_zero(&gw_node_tmp->refcount))
 			continue;
 
@@ -525,24 +519,29 @@ void batadv_gw_node_update(struct batadv_priv *bat_priv,
 	gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
 	gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
 
-	gw_node->deleted = 0;
 	if (ntohl(gateway->bandwidth_down) == 0) {
-		gw_node->deleted = jiffies;
 		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 			   "Gateway %pM removed from gateway list\n",
 			   orig_node->orig);
 
 		/* Note: We don't need a NULL check here, since curr_gw never
 		 * gets dereferenced.
 		 */
+		spin_lock_bh(&bat_priv->gw.list_lock);
+		hlist_del_init_rcu(&gw_node->list);
+		spin_unlock_bh(&bat_priv->gw.list_lock);
+
+		batadv_gw_node_free_ref(gw_node);
+
 		curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 		if (gw_node == curr_gw)
 			batadv_gw_reselect(bat_priv);
+
+		if (curr_gw)
+			batadv_gw_node_free_ref(curr_gw);
 	}
 
 out:
-	if (curr_gw)
-		batadv_gw_node_free_ref(curr_gw);
 	if (gw_node)
 		batadv_gw_node_free_ref(gw_node);
 }
@@ -558,39 +557,19 @@ void batadv_gw_node_delete(struct batadv_priv *bat_priv,
 	batadv_gw_node_update(bat_priv, orig_node, &gateway);
 }
 
-void batadv_gw_node_purge(struct batadv_priv *bat_priv)
+void batadv_gw_node_free(struct batadv_priv *bat_priv)
 {
-	struct batadv_gw_node *gw_node, *curr_gw;
+	struct batadv_gw_node *gw_node;
 	struct hlist_node *node_tmp;
-	unsigned long timeout = msecs_to_jiffies(2 * BATADV_PURGE_TIMEOUT);
-	int do_reselect = 0;
-
-	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 
 	spin_lock_bh(&bat_priv->gw.list_lock);
-
 	hlist_for_each_entry_safe(gw_node, node_tmp,
 				  &bat_priv->gw.list, list) {
-		if (((!gw_node->deleted) ||
-		     (time_before(jiffies, gw_node->deleted + timeout))) &&
-		    atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE)
-			continue;
 
-		if (curr_gw == gw_node)
-			do_reselect = 1;
-
-		hlist_del_rcu(&gw_node->list);
+		hlist_del_init_rcu(&gw_node->list);
 		batadv_gw_node_free_ref(gw_node);
 	}
-
 	spin_unlock_bh(&bat_priv->gw.list_lock);
-
-	/* gw_reselect() needs to acquire the gw_list_lock */
-	if (do_reselect)
-		batadv_gw_reselect(bat_priv);
-
-	if (curr_gw)
-		batadv_gw_node_free_ref(curr_gw);
 }
 
 /* fails if orig_node has no router */
@@ -654,9 +633,6 @@ int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
 
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
-		if (gw_node->deleted)
-			continue;
-
 		/* fails if orig_node has no router */
 		if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0)
 			continue;

net/batman-adv/gateway_client.h

@@ -38,7 +38,7 @@ void batadv_gw_node_update(struct batadv_priv *bat_priv,
 			   struct batadv_tvlv_gateway_data *gateway);
 void batadv_gw_node_delete(struct batadv_priv *bat_priv,
 			   struct batadv_orig_node *orig_node);
-void batadv_gw_node_purge(struct batadv_priv *bat_priv);
+void batadv_gw_node_free(struct batadv_priv *bat_priv);
 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset);
 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, struct sk_buff *skb);
 enum batadv_dhcp_recipient

net/batman-adv/main.c

@@ -199,7 +199,7 @@ void batadv_mesh_free(struct net_device *soft_iface)
 
 	batadv_purge_outstanding_packets(bat_priv, NULL);
 
-	batadv_gw_node_purge(bat_priv);
+	batadv_gw_node_free(bat_priv);
 	batadv_nc_mesh_free(bat_priv);
 	batadv_dat_free(bat_priv);
 	batadv_bla_free(bat_priv);

net/batman-adv/originator.c

@@ -1028,7 +1028,6 @@ static void _batadv_purge_orig(struct batadv_priv *bat_priv)
 		spin_unlock_bh(list_lock);
 	}
 
-	batadv_gw_node_purge(bat_priv);
 	batadv_gw_election(bat_priv);
 }
 

net/batman-adv/types.h

@@ -328,7 +328,6 @@ enum batadv_orig_capabilities {
  * @orig_node: pointer to corresponding orig node
  * @bandwidth_down: advertised uplink download bandwidth
  * @bandwidth_up: advertised uplink upload bandwidth
- * @deleted: this struct is scheduled for deletion
  * @refcount: number of contexts the object is used
  * @rcu: struct used for freeing in an RCU-safe manner
  */
@@ -337,7 +336,6 @@ struct batadv_gw_node {
 	struct batadv_orig_node *orig_node;
 	u32 bandwidth_down;
 	u32 bandwidth_up;
-	unsigned long deleted;
 	atomic_t refcount;
 	struct rcu_head rcu;
 };