batman-adv: Convert batadv_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>

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 23ce90e..affcbb5 100644 (file)
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -31,6 +31,7 @@
 #include <linux/init.h>
 #include <linux/jiffies.h>
 #include <linux/list.h>
+#include <linux/kref.h>
 #include <linux/netdevice.h>
 #include <linux/pkt_sched.h>
 #include <linux/printk.h>
@@ -1002,7 +1003,7 @@ batadv_iv_ogm_orig_update(struct batadv_priv *bat_priv,
                neigh_addr = tmp_neigh_node->addr;
                if (batadv_compare_eth(neigh_addr, ethhdr->h_source) &&
                    tmp_neigh_node->if_incoming == if_incoming &&
-                   atomic_inc_not_zero(&tmp_neigh_node->refcount)) {
+                   kref_get_unless_zero(&tmp_neigh_node->refcount)) {
                        if (WARN(neigh_node, "too many matching neigh_nodes"))
                                batadv_neigh_node_free_ref(neigh_node);
                        neigh_node = tmp_neigh_node;
@@ -1161,7 +1162,7 @@ static int batadv_iv_ogm_calc_tq(struct batadv_orig_node *orig_node,
                if (tmp_neigh_node->if_incoming != if_incoming)
                        continue;
 
-               if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
+               if (!kref_get_unless_zero(&tmp_neigh_node->refcount))
                        continue;
 
                neigh_node = tmp_neigh_node;

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 428983a..9e3dbd8 100644 (file)
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -229,15 +229,17 @@ void batadv_hardif_neigh_free_ref(struct batadv_hardif_neigh_node *hardif_neigh)
 /**
  * batadv_neigh_node_release - release neigh_node from lists and queue for
  *  free after rcu grace period
- * @neigh_node: neigh neighbor to free
+ * @ref: kref pointer of the neigh_node
  */
-static void batadv_neigh_node_release(struct batadv_neigh_node *neigh_node)
+static void batadv_neigh_node_release(struct kref *ref)
 {
        struct hlist_node *node_tmp;
+       struct batadv_neigh_node *neigh_node;
        struct batadv_hardif_neigh_node *hardif_neigh;
        struct batadv_neigh_ifinfo *neigh_ifinfo;
        struct batadv_algo_ops *bao;
 
+       neigh_node = container_of(ref, struct batadv_neigh_node, refcount);
        bao = neigh_node->orig_node->bat_priv->bat_algo_ops;
 
        hlist_for_each_entry_safe(neigh_ifinfo, node_tmp,
@@ -262,14 +264,13 @@ static void batadv_neigh_node_release(struct batadv_neigh_node *neigh_node)
 }
 
 /**
- * batadv_neigh_node_free_ref - decrement the neighbors refcounter
- *  and possibly release it
+ * batadv_neigh_node_free_ref - decrement the neighbors refcounter and possibly
+ *  release it
  * @neigh_node: neigh neighbor to free
  */
 void batadv_neigh_node_free_ref(struct batadv_neigh_node *neigh_node)
 {
-       if (atomic_dec_and_test(&neigh_node->refcount))
-               batadv_neigh_node_release(neigh_node);
+       kref_put(&neigh_node->refcount, batadv_neigh_node_release);
 }
 
 /**
@@ -298,7 +299,7 @@ batadv_orig_router_get(struct batadv_orig_node *orig_node,
                break;
        }
 
-       if (router && !atomic_inc_not_zero(&router->refcount))
+       if (router && !kref_get_unless_zero(&router->refcount))
                router = NULL;
 
        rcu_read_unlock();
@@ -491,7 +492,7 @@ batadv_neigh_node_get(const struct batadv_orig_node *orig_node,
                if (tmp_neigh_node->if_incoming != hard_iface)
                        continue;
 
-               if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
+               if (!kref_get_unless_zero(&tmp_neigh_node->refcount))
                        continue;
 
                res = tmp_neigh_node;
@@ -649,7 +650,8 @@ batadv_neigh_node_new(struct batadv_orig_node *orig_node,
        neigh_node->orig_node = orig_node;
 
        /* extra reference for return */
-       atomic_set(&neigh_node->refcount, 2);
+       kref_init(&neigh_node->refcount);
+       kref_get(&neigh_node->refcount);
 
        spin_lock_bh(&orig_node->neigh_list_lock);
        hlist_add_head_rcu(&neigh_node->list, &orig_node->neigh_list);
@@ -1084,7 +1086,7 @@ batadv_find_best_neighbor(struct batadv_priv *bat_priv,
                                                best, if_outgoing) <= 0))
                        continue;
 
-               if (!atomic_inc_not_zero(&neigh->refcount))
+               if (!kref_get_unless_zero(&neigh->refcount))
                        continue;
 
                if (best)

diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 4a5cd8b..205310b 100644 (file)
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -73,7 +73,7 @@ static void _batadv_update_route(struct batadv_priv *bat_priv,
 
        rcu_read_lock();
        curr_router = rcu_dereference(orig_ifinfo->router);
-       if (curr_router && !atomic_inc_not_zero(&curr_router->refcount))
+       if (curr_router && !kref_get_unless_zero(&curr_router->refcount))
                curr_router = NULL;
        rcu_read_unlock();
 
@@ -101,7 +101,7 @@ static void _batadv_update_route(struct batadv_priv *bat_priv,
                batadv_neigh_node_free_ref(curr_router);
 
        /* increase refcount of new best neighbor */
-       if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
+       if (neigh_node && !kref_get_unless_zero(&neigh_node->refcount))
                neigh_node = NULL;
 
        spin_lock_bh(&orig_node->neigh_list_lock);
@@ -505,7 +505,7 @@ batadv_find_router(struct batadv_priv *bat_priv,
                if (!cand_router)
                        goto next;
 
-               if (!atomic_inc_not_zero(&cand_router->refcount)) {
+               if (!kref_get_unless_zero(&cand_router->refcount)) {
                        cand_router = NULL;
                        goto next;
                }
@@ -524,7 +524,7 @@ batadv_find_router(struct batadv_priv *bat_priv,
 
                /* mark the first possible candidate */
                if (!first_candidate) {
-                       atomic_inc(&cand_router->refcount);
+                       kref_get(&cand_router->refcount);
                        kref_get(&cand->refcount);
                        first_candidate = cand;
                        first_candidate_router = cand_router;

diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 6193c01..68ca39e 100644 (file)
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -384,7 +384,7 @@ struct batadv_neigh_node {
        spinlock_t ifinfo_lock; /* protects ifinfo_list and its members */
        struct batadv_hard_iface *if_incoming;
        unsigned long last_seen;
-       atomic_t refcount;
+       struct kref refcount;
        struct rcu_head rcu;
 };