batman-adv: Convert batadv_tvlv_handler 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/main.c b/net/batman-adv/main.c
index 4b6c258..568c550 100644 (file)
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -625,15 +625,27 @@ __be32 batadv_skb_crc32(struct sk_buff *skb, u8 *payload_ptr)
 }
 
 /**
- * batadv_tvlv_handler_free_ref - decrement the tvlv handler refcounter and
- *  possibly free it
+ * batadv_tvlv_handler_release - release tvlv handler from lists and queue for
+ *  free after rcu grace period
+ * @ref: kref pointer of the tvlv
+ */
+static void batadv_tvlv_handler_release(struct kref *ref)
+{
+       struct batadv_tvlv_handler *tvlv_handler;
+
+       tvlv_handler = container_of(ref, struct batadv_tvlv_handler, refcount);
+       kfree_rcu(tvlv_handler, rcu);
+}
+
+/**
+ * batadv_tvlv_handler_free_ref - decrement the tvlv container refcounter and
+ *  possibly release it
  * @tvlv_handler: the tvlv handler to free
  */
 static void
 batadv_tvlv_handler_free_ref(struct batadv_tvlv_handler *tvlv_handler)
 {
-       if (atomic_dec_and_test(&tvlv_handler->refcount))
-               kfree_rcu(tvlv_handler, rcu);
+       kref_put(&tvlv_handler->refcount, batadv_tvlv_handler_release);
 }
 
 /**
@@ -659,7 +671,7 @@ static struct batadv_tvlv_handler
                if (tvlv_handler_tmp->version != version)
                        continue;
 
-               if (!atomic_inc_not_zero(&tvlv_handler_tmp->refcount))
+               if (!kref_get_unless_zero(&tvlv_handler_tmp->refcount))
                        continue;
 
                tvlv_handler = tvlv_handler_tmp;
@@ -1112,7 +1124,7 @@ void batadv_tvlv_handler_register(struct batadv_priv *bat_priv,
        tvlv_handler->type = type;
        tvlv_handler->version = version;
        tvlv_handler->flags = flags;
-       atomic_set(&tvlv_handler->refcount, 1);
+       kref_init(&tvlv_handler->refcount);
        INIT_HLIST_NODE(&tvlv_handler->list);
 
        spin_lock_bh(&bat_priv->tvlv.handler_list_lock);

diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index c55925b..f89dd97 100644 (file)
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -1293,7 +1293,7 @@ struct batadv_tvlv_handler {
        u8 type;
        u8 version;
        u8 flags;
-       atomic_t refcount;
+       struct kref refcount;
        struct rcu_head rcu;
 };