batman-adv: Move OGM rebroadcast stats to orig_ifinfo

B.A.T.M.A.N. IV requires the number of rebroadcast from a neighboring
originator. These statistics are gathered per interface which transmitted
the OGM (and then received it again). Since an originator is not interface
specific, a resizable array was used in each originator.

This resizable array had an entry for each interface and had to be resizes
(for all OGMs) when the number of active interface was modified. This could
cause problems when a large number of interface is added and not enough
continuous memory is available to allocate the array.

There is already a per interface originator structure "batadv_orig_ifinfo"
which can be used to store this information.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

1 files changed, 28 insertions, 19 deletions

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index 2f0d42f2f913..781c5b6e6e8e 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -763,11 +763,6 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
 	hard_iface->soft_iface = soft_iface;
 	bat_priv = netdev_priv(hard_iface->soft_iface);
 
-	if (bat_priv->num_ifaces >= UINT_MAX) {
-		ret = -ENOSPC;
-		goto err_dev;
-	}
-
 	ret = netdev_master_upper_dev_link(hard_iface->net_dev,
 					   soft_iface, NULL, NULL, NULL);
 	if (ret)
@@ -777,16 +772,7 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
 	if (ret < 0)
 		goto err_upper;
 
-	hard_iface->if_num = bat_priv->num_ifaces;
-	bat_priv->num_ifaces++;
 	hard_iface->if_status = BATADV_IF_INACTIVE;
-	ret = batadv_orig_hash_add_if(hard_iface, bat_priv->num_ifaces);
-	if (ret < 0) {
-		bat_priv->algo_ops->iface.disable(hard_iface);
-		bat_priv->num_ifaces--;
-		hard_iface->if_status = BATADV_IF_NOT_IN_USE;
-		goto err_upper;
-	}
 
 	kref_get(&hard_iface->refcount);
 	hard_iface->batman_adv_ptype.type = ethertype;
@@ -834,6 +820,33 @@ err:
 }
 
 /**
+ * batadv_hardif_cnt() - get number of interfaces enslaved to soft interface
+ * @soft_iface: soft interface to check
+ *
+ * This function is only using RCU for locking - the result can therefore be
+ * off when another functions is modifying the list at the same time. The
+ * caller can use the rtnl_lock to make sure that the count is accurate.
+ *
+ * Return: number of connected/enslaved hard interfaces
+ */
+static size_t batadv_hardif_cnt(const struct net_device *soft_iface)
+{
+	struct batadv_hard_iface *hard_iface;
+	size_t count = 0;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
+		if (hard_iface->soft_iface != soft_iface)
+			continue;
+
+		count++;
+	}
+	rcu_read_unlock();
+
+	return count;
+}
+
+/**
  * batadv_hardif_disable_interface() - Remove hard interface from soft interface
  * @hard_iface: hard interface to be removed
  * @autodel: whether to delete soft interface when it doesn't contain any other
@@ -855,9 +868,6 @@ void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface,
 	dev_remove_pack(&hard_iface->batman_adv_ptype);
 	batadv_hardif_put(hard_iface);
 
-	bat_priv->num_ifaces--;
-	batadv_orig_hash_del_if(hard_iface, bat_priv->num_ifaces);
-
 	primary_if = batadv_primary_if_get_selected(bat_priv);
 	if (hard_iface == primary_if) {
 		struct batadv_hard_iface *new_if;
@@ -881,7 +891,7 @@ void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface,
 	batadv_hardif_recalc_extra_skbroom(hard_iface->soft_iface);
 
 	/* nobody uses this interface anymore */
-	if (bat_priv->num_ifaces == 0) {
+	if (batadv_hardif_cnt(hard_iface->soft_iface) <= 1) {
 		batadv_gw_check_client_stop(bat_priv);
 
 		if (autodel == BATADV_IF_CLEANUP_AUTO)
@@ -917,7 +927,6 @@ batadv_hardif_add_interface(struct net_device *net_dev)
 	if (ret)
 		goto free_if;
 
-	hard_iface->if_num = 0;
 	hard_iface->net_dev = net_dev;
 	hard_iface->soft_iface = NULL;
 	hard_iface->if_status = BATADV_IF_NOT_IN_USE;