batman-adv: Convert batadv_orig_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>
diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 8b2ef8d..eacd0e5 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -18,6 +18,7 @@
 #include "originator.h"
 #include "main.h"
 
+#include <linux/atomic.h>
 #include <linux/errno.h>
 #include <linux/etherdevice.h>
 #include <linux/fs.h>
@@ -775,14 +776,17 @@
 /**
  * batadv_orig_node_release - release orig_node from lists and queue for
  *  free after rcu grace period
- * @orig_node: the orig node to free
+ * @ref: kref pointer of the orig_node
  */
-static void batadv_orig_node_release(struct batadv_orig_node *orig_node)
+static void batadv_orig_node_release(struct kref *ref)
 {
 	struct hlist_node *node_tmp;
 	struct batadv_neigh_node *neigh_node;
+	struct batadv_orig_node *orig_node;
 	struct batadv_orig_ifinfo *orig_ifinfo;
 
+	orig_node = container_of(ref, struct batadv_orig_node, refcount);
+
 	spin_lock_bh(&orig_node->neigh_list_lock);
 
 	/* for all neighbors towards this originator ... */
@@ -812,8 +816,7 @@
  */
 void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node)
 {
-	if (atomic_dec_and_test(&orig_node->refcount))
-		batadv_orig_node_release(orig_node);
+	kref_put(&orig_node->refcount, batadv_orig_node_release);
 }
 
 void batadv_originator_free(struct batadv_priv *bat_priv)
@@ -885,7 +888,8 @@
 	batadv_nc_init_orig(orig_node);
 
 	/* extra reference for return */
-	atomic_set(&orig_node->refcount, 2);
+	kref_init(&orig_node->refcount);
+	kref_get(&orig_node->refcount);
 
 	orig_node->bat_priv = bat_priv;
 	ether_addr_copy(orig_node->orig, addr);