batman-adv: protect neighbor list with rcu locks

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>

1 files changed, 28 insertions, 7 deletions

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 68b04e77f4d7..6cb9af3f89e5 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -67,6 +67,14 @@ void neigh_node_free_ref(struct kref *refcount)
         kfree(neigh_node);
 }
 
+static void neigh_node_free_rcu(struct rcu_head *rcu)
+{
+        struct neigh_node *neigh_node;
+
+        neigh_node = container_of(rcu, struct neigh_node, rcu);
+        kref_put(&neigh_node->refcount, neigh_node_free_ref);
+}
+
 struct neigh_node *create_neighbor(struct orig_node *orig_node,
                                    struct orig_node *orig_neigh_node,
                                    uint8_t *neigh,
@@ -89,7 +97,9 @@ struct neigh_node *create_neighbor(struct orig_node *orig_node,
         neigh_node->if_incoming = if_incoming;
         kref_init(&neigh_node->refcount);
 
-        hlist_add_head(&neigh_node->list, &orig_node->neigh_list);
+        spin_lock_bh(&orig_node->neigh_list_lock);
+        hlist_add_head_rcu(&neigh_node->list, &orig_node->neigh_list);
+        spin_unlock_bh(&orig_node->neigh_list_lock);
         return neigh_node;
 }
 
@@ -100,13 +110,17 @@ static void free_orig_node(void *data, void *arg)
         struct orig_node *orig_node = (struct orig_node *)data;
         struct bat_priv *bat_priv = (struct bat_priv *)arg;
 
+        spin_lock_bh(&orig_node->neigh_list_lock);
+
         /* for all neighbors towards this originator ... */
         hlist_for_each_entry_safe(neigh_node, node, node_tmp,
                                   &orig_node->neigh_list, list) {
-                hlist_del(&neigh_node->list);
-                kref_put(&neigh_node->refcount, neigh_node_free_ref);
+                hlist_del_rcu(&neigh_node->list);
+                call_rcu(&neigh_node->rcu, neigh_node_free_rcu);
         }
 
+        spin_unlock_bh(&orig_node->neigh_list_lock);
+
         frag_list_free(&orig_node->frag_list);
         hna_global_del_orig(bat_priv, orig_node, "originator timed out");
 
@@ -151,6 +165,7 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)
                 return NULL;
 
         INIT_HLIST_HEAD(&orig_node->neigh_list);
+        spin_lock_init(&orig_node->neigh_list_lock);
 
         memcpy(orig_node->orig, addr, ETH_ALEN);
         orig_node->router = NULL;
@@ -200,6 +215,8 @@ static bool purge_orig_neighbors(struct bat_priv *bat_priv,
 
         *best_neigh_node = NULL;
 
+        spin_lock_bh(&orig_node->neigh_list_lock);
+
         /* for all neighbors towards this originator ... */
         hlist_for_each_entry_safe(neigh_node, node, node_tmp,
                                   &orig_node->neigh_list, list) {
@@ -225,14 +242,16 @@ static bool purge_orig_neighbors(struct bat_priv *bat_priv,
 
                         neigh_purged = true;
 
-                        hlist_del(&neigh_node->list);
-                        kref_put(&neigh_node->refcount, neigh_node_free_ref);
+                        hlist_del_rcu(&neigh_node->list);
+                        call_rcu(&neigh_node->rcu, neigh_node_free_rcu);
                 } else {
                         if ((!*best_neigh_node) ||
                             (neigh_node->tq_avg > (*best_neigh_node)->tq_avg))
                                 *best_neigh_node = neigh_node;
                 }
         }
+
+        spin_unlock_bh(&orig_node->neigh_list_lock);
         return neigh_purged;
 }
 
@@ -384,11 +403,13 @@ int orig_seq_print_text(struct seq_file *seq, void *offset)
                                    neigh_node->addr,
                                    neigh_node->if_incoming->net_dev->name);
 
-                        hlist_for_each_entry(neigh_node, node,
-                                             &orig_node->neigh_list, list) {
+                        rcu_read_lock();
+                        hlist_for_each_entry_rcu(neigh_node, node,
+                                                 &orig_node->neigh_list, list) {
                                 seq_printf(seq, " %pM (%3i)", neigh_node->addr,
                                                 neigh_node->tq_avg);
                         }
+                        rcu_read_unlock();
 
                         seq_printf(seq, "\n");
                         batman_count++;