batman-adv: Convert batadv_hardif_neigh_node to kref

batman-adv uses a self-written reference implementation which is just based
on atomic_t. This is less obvious when reading the code than kref and
therefore increases the change that the reference counting will be missed.

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

1 files changed, 12 insertions, 8 deletions

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index d4a30db0158a..7710595ffc42 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -23,6 +23,7 @@
 #include <linux/fs.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
+#include <linux/kref.h>
 #include <linux/list.h>
 #include <linux/lockdep.h>
 #include <linux/netdevice.h>
@@ -196,11 +197,15 @@ void batadv_neigh_ifinfo_free_ref(struct batadv_neigh_ifinfo *neigh_ifinfo)
 /**
  * batadv_hardif_neigh_release - release hardif neigh node from lists and
  *  queue for free after rcu grace period
- * @hardif_neigh: hardif neigh neighbor to free
+ * @ref: kref pointer of the neigh_node
  */
-static void
-batadv_hardif_neigh_release(struct batadv_hardif_neigh_node *hardif_neigh)
+static void batadv_hardif_neigh_release(struct kref *ref)
 {
+        struct batadv_hardif_neigh_node *hardif_neigh;
+
+        hardif_neigh = container_of(ref, struct batadv_hardif_neigh_node,
+                                    refcount);
+
         spin_lock_bh(&hardif_neigh->if_incoming->neigh_list_lock);
         hlist_del_init_rcu(&hardif_neigh->list);
         spin_unlock_bh(&hardif_neigh->if_incoming->neigh_list_lock);
@@ -216,8 +221,7 @@ batadv_hardif_neigh_release(struct batadv_hardif_neigh_node *hardif_neigh)
  */
 void batadv_hardif_neigh_free_ref(struct batadv_hardif_neigh_node *hardif_neigh)
 {
-        if (atomic_dec_and_test(&hardif_neigh->refcount))
-                batadv_hardif_neigh_release(hardif_neigh);
+        kref_put(&hardif_neigh->refcount, batadv_hardif_neigh_release);
 }
 
 /**
@@ -529,7 +533,7 @@ batadv_hardif_neigh_create(struct batadv_hard_iface *hard_iface,
         hardif_neigh->if_incoming = hard_iface;
         hardif_neigh->last_seen = jiffies;
 
-        atomic_set(&hardif_neigh->refcount, 1);
+        kref_init(&hardif_neigh->refcount);
 
         if (bat_priv->bat_algo_ops->bat_hardif_neigh_init)
                 bat_priv->bat_algo_ops->bat_hardif_neigh_init(hardif_neigh);
@@ -584,7 +588,7 @@ batadv_hardif_neigh_get(const struct batadv_hard_iface *hard_iface,
                 if (!batadv_compare_eth(tmp_hardif_neigh->addr, neigh_addr))
                         continue;
 
-                if (!atomic_inc_not_zero(&tmp_hardif_neigh->refcount))
+                if (!kref_get_unless_zero(&tmp_hardif_neigh->refcount))
                         continue;
 
                 hardif_neigh = tmp_hardif_neigh;
@@ -648,7 +652,7 @@ batadv_neigh_node_new(struct batadv_orig_node *orig_node,
         spin_unlock_bh(&orig_node->neigh_list_lock);
 
         /* increment unique neighbor refcount */
-        atomic_inc(&hardif_neigh->refcount);
+        kref_get(&hardif_neigh->refcount);
 
         batadv_dbg(BATADV_DBG_BATMAN, orig_node->bat_priv,
                    "Creating new neighbor %pM for orig_node %pM on interface %s\n",