batman-adv: Convert batadv_tt_orig_list_entry 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/translation-table.c b/net/batman-adv/translation-table.c
index 0dc8a5c..68494a1 100644 (file)
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -31,6 +31,7 @@
 #include <linux/jhash.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>
@@ -346,22 +347,28 @@ static void batadv_tt_global_size_dec(struct batadv_orig_node *orig_node,
 /**
  * batadv_tt_orig_list_entry_release - release tt orig entry from lists and
  *  queue for free after rcu grace period
- * @orig_entry: tt orig entry to be free'd
+ * @ref: kref pointer of the tt orig entry
  */
-static void
-batadv_tt_orig_list_entry_release(struct batadv_tt_orig_list_entry *orig_entry)
+static void batadv_tt_orig_list_entry_release(struct kref *ref)
 {
+       struct batadv_tt_orig_list_entry *orig_entry;
+
+       orig_entry = container_of(ref, struct batadv_tt_orig_list_entry,
+                                 refcount);
+
        batadv_orig_node_free_ref(orig_entry->orig_node);
        kfree_rcu(orig_entry, rcu);
 }
 
+/**
+ * batadv_tt_orig_list_entry_free_ref - decrement the tt orig entry refcounter
+ *  and possibly release it
+ * @orig_entry: tt orig entry to be free'd
+ */
 static void
 batadv_tt_orig_list_entry_free_ref(struct batadv_tt_orig_list_entry *orig_entry)
 {
-       if (!atomic_dec_and_test(&orig_entry->refcount))
-               return;
-
-       batadv_tt_orig_list_entry_release(orig_entry);
+       kref_put(&orig_entry->refcount, batadv_tt_orig_list_entry_release);
 }
 
 /**
@@ -1270,7 +1277,7 @@ batadv_tt_global_orig_entry_find(const struct batadv_tt_global_entry *entry,
        hlist_for_each_entry_rcu(tmp_orig_entry, head, list) {
                if (tmp_orig_entry->orig_node != orig_node)
                        continue;
-               if (!atomic_inc_not_zero(&tmp_orig_entry->refcount))
+               if (!kref_get_unless_zero(&tmp_orig_entry->refcount))
                        continue;
 
                orig_entry = tmp_orig_entry;
@@ -1331,7 +1338,8 @@ batadv_tt_global_orig_entry_add(struct batadv_tt_global_entry *tt_global,
        batadv_tt_global_size_inc(orig_node, tt_global->common.vid);
        orig_entry->orig_node = orig_node;
        orig_entry->ttvn = ttvn;
-       atomic_set(&orig_entry->refcount, 2);
+       kref_init(&orig_entry->refcount);
+       kref_get(&orig_entry->refcount);
 
        spin_lock_bh(&tt_global->list_lock);
        hlist_add_head_rcu(&orig_entry->list,

diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index f89dd97..17f97ff 100644 (file)
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -1014,7 +1014,7 @@ struct batadv_tt_orig_list_entry {
        struct batadv_orig_node *orig_node;
        u8 ttvn;
        struct hlist_node list;
-       atomic_t refcount;
+       struct kref refcount;
        struct rcu_head rcu;
 };