[PATCH RFC batadv v3 2/4] batman-adv: remove global hardif list

From: Nora Schiffer <[email protected]>

With interfaces being kept track of as iflink private data, there is no
need for the global list anymore. batadv_hardif_get_by_netdev() can now
use netdev_master_upper_dev_get()+netdev_lower_dev_get_private() to find
the hardif corresponding to a netdev.
---
 net/batman-adv/hard-interface.c | 36 +++++++++++++-----------------------
 net/batman-adv/hard-interface.h |  2 +-
 net/batman-adv/main.c           |  5 -----
 net/batman-adv/main.h           |  1 -
 net/batman-adv/netlink.c        |  2 ++
 net/batman-adv/types.h          |  3 ---
 6 files changed, 16 insertions(+), 33 deletions(-)

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index ba18d322..e9b850ab 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -63,6 +63,7 @@ void batadv_hardif_release(struct kref *ref)
 	struct batadv_hard_iface *hard_iface;
 
 	hard_iface = container_of(ref, struct batadv_hard_iface, refcount);
+	netdev_put(hard_iface->mesh_iface, &hard_iface->meshif_dev_tracker);
 	netdev_put(hard_iface->net_dev, &hard_iface->dev_tracker);
 
 	kfree_rcu(hard_iface, rcu);
@@ -75,21 +76,21 @@ void batadv_hardif_release(struct kref *ref)
  * Return: batadv_hard_iface of net_dev (with increased refcnt), NULL on errors
  */
 struct batadv_hard_iface *
-batadv_hardif_get_by_netdev(const struct net_device *net_dev)
+batadv_hardif_get_by_netdev(struct net_device *net_dev)
 {
 	struct batadv_hard_iface *hard_iface;
+	struct net_device *mesh_iface;
 
-	rcu_read_lock();
-	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
-		if (hard_iface->net_dev == net_dev &&
-		    kref_get_unless_zero(&hard_iface->refcount))
-			goto out;
-	}
+	ASSERT_RTNL();
 
-	hard_iface = NULL;
+	mesh_iface = netdev_master_upper_dev_get(net_dev);
+	if (!mesh_iface || !batadv_meshif_is_valid(mesh_iface))
+		return NULL;
+
+	hard_iface = netdev_lower_dev_get_private(mesh_iface, net_dev);
+	if (!kref_get_unless_zero(&hard_iface->refcount))
+		return NULL;
 
-out:
-	rcu_read_unlock();
 	return hard_iface;
 }
 
@@ -759,10 +760,8 @@ int batadv_hardif_enable_interface(struct net_device *net_dev,
 	netdev_hold(net_dev, &hard_iface->dev_tracker, GFP_ATOMIC);
 	hard_iface->net_dev = net_dev;
 
-	hard_iface->mesh_iface = NULL;
 	hard_iface->if_status = BATADV_IF_INACTIVE;
 
-	INIT_LIST_HEAD(&hard_iface->list);
 	INIT_HLIST_HEAD(&hard_iface->neigh_list);
 
 	mutex_init(&hard_iface->bat_iv.ogm_buff_mutex);
@@ -781,6 +780,7 @@ int batadv_hardif_enable_interface(struct net_device *net_dev,
 	hard_iface->mesh_iface = mesh_iface;
 	bat_priv = netdev_priv(hard_iface->mesh_iface);
 
+	batadv_hardif_generation++;
 	ret = netdev_master_upper_dev_link(hard_iface->net_dev,
 					   mesh_iface, hard_iface, NULL, NULL);
 	if (ret)
@@ -826,16 +826,11 @@ int batadv_hardif_enable_interface(struct net_device *net_dev,
 	if (bat_priv->algo_ops->iface.enabled)
 		bat_priv->algo_ops->iface.enabled(hard_iface);
 
-	kref_get(&hard_iface->refcount);
-	list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);
-	batadv_hardif_generation++;
-
 	return 0;
 
 err_upper:
 	netdev_upper_dev_unlink(hard_iface->net_dev, mesh_iface);
 err_dev:
-	hard_iface->mesh_iface = NULL;
 	netdev_put(mesh_iface, &hard_iface->meshif_dev_tracker);
 	batadv_hardif_put(hard_iface);
 	return ret;
@@ -881,10 +876,6 @@ void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface)
 	if (hard_iface->if_status != BATADV_IF_INACTIVE)
 		goto out;
 
-	list_del_rcu(&hard_iface->list);
-	batadv_hardif_put(hard_iface);
-	batadv_hardif_generation++;
-
 	batadv_info(hard_iface->mesh_iface, "Removing interface: %s\n",
 		    hard_iface->net_dev->name);
 	dev_remove_pack(&hard_iface->batman_adv_ptype);
@@ -906,8 +897,8 @@ void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface)
 	/* delete all references to this hard_iface */
 	batadv_purge_orig_ref(bat_priv);
 	batadv_purge_outstanding_packets(bat_priv, hard_iface);
-	netdev_put(hard_iface->mesh_iface, &hard_iface->meshif_dev_tracker);
 
+	batadv_hardif_generation++;
 	netdev_upper_dev_unlink(hard_iface->net_dev, hard_iface->mesh_iface);
 	batadv_hardif_recalc_extra_skbroom(hard_iface->mesh_iface);
 
@@ -915,7 +906,6 @@ void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface)
 	if (batadv_hardif_cnt(hard_iface->mesh_iface) <= 1)
 		batadv_gw_check_client_stop(bat_priv);
 
-	hard_iface->mesh_iface = NULL;
 	batadv_hardif_put(hard_iface);
 
 out:
diff --git a/net/batman-adv/hard-interface.h b/net/batman-adv/hard-interface.h
index 845ff5d2..b2fd82a6 100644
--- a/net/batman-adv/hard-interface.h
+++ b/net/batman-adv/hard-interface.h
@@ -74,7 +74,7 @@ u32 batadv_netdev_get_wifi_flags(struct net_device *net_dev);
 u32 batadv_hardif_get_wifi_flags(struct batadv_hard_iface *hard_iface);
 bool batadv_is_wifi_hardif(struct batadv_hard_iface *hard_iface);
 struct batadv_hard_iface*
-batadv_hardif_get_by_netdev(const struct net_device *net_dev);
+batadv_hardif_get_by_netdev(struct net_device *net_dev);
 int batadv_hardif_enable_interface(struct net_device *net_dev,
 				   struct net_device *mesh_iface);
 void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface);
diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index 3c457228..1d82f3a8 100644
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -59,10 +59,6 @@
 #include "tp_meter.h"
 #include "translation-table.h"
 
-/* List manipulations on hardif_list have to be rtnl_lock()'ed,
- * list traversals just rcu-locked
- */
-struct list_head batadv_hardif_list;
 unsigned int batadv_hardif_generation;
 static int (*batadv_rx_handler[256])(struct sk_buff *skb,
 				     struct batadv_hard_iface *recv_if);
@@ -95,7 +91,6 @@ static int __init batadv_init(void)
 	if (ret < 0)
 		return ret;
 
-	INIT_LIST_HEAD(&batadv_hardif_list);
 	batadv_algo_init();
 
 	batadv_recv_handler_init();
diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h
index f68fc8b7..e3414504 100644
--- a/net/batman-adv/main.h
+++ b/net/batman-adv/main.h
@@ -226,7 +226,6 @@ static inline int batadv_print_vid(unsigned short vid)
 		return -1;
 }
 
-extern struct list_head batadv_hardif_list;
 extern unsigned int batadv_hardif_generation;
 
 extern struct workqueue_struct *batadv_event_workqueue;
diff --git a/net/batman-adv/netlink.c b/net/batman-adv/netlink.c
index 43f307d5..6fb0bebc 100644
--- a/net/batman-adv/netlink.c
+++ b/net/batman-adv/netlink.c
@@ -1211,7 +1211,9 @@ batadv_netlink_get_hardif_from_ifindex(struct batadv_priv *bat_priv,
 	if (!hard_dev)
 		return ERR_PTR(-ENODEV);
 
+	rtnl_lock();
 	hard_iface = batadv_hardif_get_by_netdev(hard_dev);
+	rtnl_unlock();
 	if (!hard_iface)
 		goto err_put_harddev;
 
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 5eb0371d..1ee663c3 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -208,9 +208,6 @@ struct batadv_wifi_net_device_state {
  * struct batadv_hard_iface - network device known to batman-adv
  */
 struct batadv_hard_iface {
-	/** @list: list node for batadv_hardif_list */
-	struct list_head list;
-
 	/** @if_status: status of the interface for batman-adv */
 	char if_status;
 

-- 
2.47.3