batman-adv: protect bonding with rcu locks

bonding / alternating candidates need to be secured by rcu locks
as well. This patch therefore converts the bonding list
from a plain pointer list to a rcu securable lists and references
the bonding candidates.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>

1 files changed, 21 insertions, 4 deletions

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 71dfc24e961b..a85eadca6b2d 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -75,6 +75,14 @@ static void neigh_node_free_rcu(struct rcu_head *rcu)
         kref_put(&neigh_node->refcount, neigh_node_free_ref);
 }
 
+void neigh_node_free_rcu_bond(struct rcu_head *rcu)
+{
+        struct neigh_node *neigh_node;
+
+        neigh_node = container_of(rcu, struct neigh_node, rcu_bond);
+        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,
@@ -91,6 +99,7 @@ struct neigh_node *create_neighbor(struct orig_node *orig_node,
                 return NULL;
 
         INIT_HLIST_NODE(&neigh_node->list);
+        INIT_LIST_HEAD(&neigh_node->bonding_list);
 
         memcpy(neigh_node->addr, neigh, ETH_ALEN);
         neigh_node->orig_node = orig_neigh_node;
@@ -106,13 +115,20 @@ struct neigh_node *create_neighbor(struct orig_node *orig_node,
 void orig_node_free_ref(struct kref *refcount)
 {
         struct hlist_node *node, *node_tmp;
-        struct neigh_node *neigh_node;
+        struct neigh_node *neigh_node, *tmp_neigh_node;
         struct orig_node *orig_node;
 
         orig_node = container_of(refcount, struct orig_node, refcount);
 
         spin_lock_bh(&orig_node->neigh_list_lock);
 
+        /* for all bonding members ... */
+        list_for_each_entry_safe(neigh_node, tmp_neigh_node,
+                                 &orig_node->bond_list, bonding_list) {
+                list_del_rcu(&neigh_node->bonding_list);
+                call_rcu(&neigh_node->rcu_bond, neigh_node_free_rcu_bond);
+        }
+
         /* for all neighbors towards this originator ... */
         hlist_for_each_entry_safe(neigh_node, node, node_tmp,
                                   &orig_node->neigh_list, list) {
@@ -207,6 +223,7 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)
                 return NULL;
 
         INIT_HLIST_HEAD(&orig_node->neigh_list);
+        INIT_LIST_HEAD(&orig_node->bond_list);
         spin_lock_init(&orig_node->ogm_cnt_lock);
         spin_lock_init(&orig_node->neigh_list_lock);
         kref_init(&orig_node->refcount);
@@ -220,6 +237,8 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)
         orig_node->batman_seqno_reset = jiffies - 1
                                         - msecs_to_jiffies(RESET_PROTECTION_MS);
 
+        atomic_set(&orig_node->bond_candidates, 0);
+
         size = bat_priv->num_ifaces * sizeof(unsigned long) * NUM_WORDS;
 
         orig_node->bcast_own = kzalloc(size, GFP_ATOMIC);
@@ -295,6 +314,7 @@ static bool purge_orig_neighbors(struct bat_priv *bat_priv,
                         neigh_purged = true;
 
                         hlist_del_rcu(&neigh_node->list);
+                        bonding_candidate_del(orig_node, neigh_node);
                         call_rcu(&neigh_node->rcu, neigh_node_free_rcu);
                 } else {
                         if ((!*best_neigh_node) ||
@@ -326,9 +346,6 @@ static bool purge_orig_node(struct bat_priv *bat_priv,
                                       best_neigh_node,
                                       orig_node->hna_buff,
                                       orig_node->hna_buff_len);
-                        /* update bonding candidates, we could have lost
-                         * some candidates. */
-                        update_bonding_candidates(orig_node);
                 }
         }