batman-adv: Convert batadv_nc_path 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/network-coding.c b/net/batman-adv/network-coding.c
index 7a1216e..371fc6b 100644 (file)
--- a/net/batman-adv/network-coding.c
+++ b/net/batman-adv/network-coding.c
@@ -233,14 +233,27 @@ static void batadv_nc_node_free_ref(struct batadv_nc_node *nc_node)
 }
 
 /**
- * batadv_nc_path_free_ref - decrements the nc path refcounter and possibly
- * frees it
- * @nc_path: the nc node to free
+ * batadv_nc_path_release - release nc_path from lists and queue for free after
+ *  rcu grace period
+ * @ref: kref pointer of the nc_path
+ */
+static void batadv_nc_path_release(struct kref *ref)
+{
+       struct batadv_nc_path *nc_path;
+
+       nc_path = container_of(ref, struct batadv_nc_path, refcount);
+
+       kfree_rcu(nc_path, rcu);
+}
+
+/**
+ * batadv_nc_path_free_ref - decrement the nc_path refcounter and possibly
+ *  release it
+ * @nc_path: nc_path to be free'd
  */
 static void batadv_nc_path_free_ref(struct batadv_nc_path *nc_path)
 {
-       if (atomic_dec_and_test(&nc_path->refcount))
-               kfree_rcu(nc_path, rcu);
+       kref_put(&nc_path->refcount, batadv_nc_path_release);
 }
 
 /**
@@ -545,7 +558,7 @@ batadv_nc_hash_find(struct batadv_hashtable *hash,
                if (!batadv_nc_hash_compare(&nc_path->hash_entry, data))
                        continue;
 
-               if (!atomic_inc_not_zero(&nc_path->refcount))
+               if (!kref_get_unless_zero(&nc_path->refcount))
                        continue;
 
                nc_path_tmp = nc_path;
@@ -972,7 +985,8 @@ static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
        /* Initialize nc_path */
        INIT_LIST_HEAD(&nc_path->packet_list);
        spin_lock_init(&nc_path->packet_list_lock);
-       atomic_set(&nc_path->refcount, 2);
+       kref_init(&nc_path->refcount);
+       kref_get(&nc_path->refcount);
        nc_path->last_valid = jiffies;
        ether_addr_copy(nc_path->next_hop, dst);
        ether_addr_copy(nc_path->prev_hop, src);

diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 05421af..b3d9b5b 100644 (file)
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -1087,7 +1087,7 @@ struct batadv_nc_node {
 struct batadv_nc_path {
        struct hlist_node hash_entry;
        struct rcu_head rcu;
-       atomic_t refcount;
+       struct kref refcount;
        struct list_head packet_list;
        spinlock_t packet_list_lock; /* Protects packet_list */
        u8 next_hop[ETH_ALEN];