From: Sven Eckelmann sven@narfation.org
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 --- net/batman-adv/translation-table.c | 64 +++++++++++++++++++++++++++++--------- net/batman-adv/types.h | 2 +- 2 files changed, 51 insertions(+), 15 deletions(-)
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index 96b1571213bd..11882793f0a4 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -142,7 +142,7 @@ batadv_tt_hash_find(struct batadv_hashtable *hash, const u8 *addr, if (tt->vid != vid) continue;
- if (!atomic_inc_not_zero(&tt->refcount)) + if (!kref_get_unless_zero(&tt->refcount)) continue;
tt_tmp = tt; @@ -203,25 +203,59 @@ batadv_tt_global_hash_find(struct batadv_priv *bat_priv, const u8 *addr, return tt_global_entry; }
-static void -batadv_tt_local_entry_free_ref(struct batadv_tt_local_entry *tt_local_entry) +/** + * batadv_tt_local_entry_release - release tt_local_entry from lists and queue + * for free after rcu grace period + * @ref: kref pointer of the nc_node + */ +static void batadv_tt_local_entry_release(struct kref *ref) { - if (atomic_dec_and_test(&tt_local_entry->common.refcount)) - kfree_rcu(tt_local_entry, common.rcu); + struct batadv_tt_local_entry *tt_local_entry; + + tt_local_entry = container_of(ref, struct batadv_tt_local_entry, + common.refcount); + + kfree_rcu(tt_local_entry, common.rcu); }
/** - * batadv_tt_global_entry_free_ref - decrement the refcounter for a - * tt_global_entry and possibly free it - * @tt_global_entry: the object to free + * batadv_tt_local_entry_free_ref - decrement the tt_local_entry refcounter and + * possibly release it + * @tt_local_entry: tt_local_entry to be free'd + */ +static void +batadv_tt_local_entry_free_ref(struct batadv_tt_local_entry *tt_local_entry) +{ + kref_put(&tt_local_entry->common.refcount, + batadv_tt_local_entry_release); +} + +/** + * batadv_tt_global_entry_release - release tt_global_entry from lists and queue + * for free after rcu grace period + * @ref: kref pointer of the nc_node + */ +static void batadv_tt_global_entry_release(struct kref *ref) +{ + struct batadv_tt_global_entry *tt_global_entry; + + tt_global_entry = container_of(ref, struct batadv_tt_global_entry, + common.refcount); + + batadv_tt_global_del_orig_list(tt_global_entry); + kfree_rcu(tt_global_entry, common.rcu); +} + +/** + * batadv_tt_global_entry_free_ref - decrement the tt_global_entry refcounter + * and possibly release it + * @tt_global_entry: tt_global_entry to be free'd */ static void batadv_tt_global_entry_free_ref(struct batadv_tt_global_entry *tt_global_entry) { - if (atomic_dec_and_test(&tt_global_entry->common.refcount)) { - batadv_tt_global_del_orig_list(tt_global_entry); - kfree_rcu(tt_global_entry, common.rcu); - } + kref_put(&tt_global_entry->common.refcount, + batadv_tt_global_entry_release); }
/** @@ -633,7 +667,8 @@ bool batadv_tt_local_add(struct net_device *soft_iface, const u8 *addr, tt_local->common.vid = vid; if (batadv_is_wifi_netdev(in_dev)) tt_local->common.flags |= BATADV_TT_CLIENT_WIFI; - atomic_set(&tt_local->common.refcount, 2); + kref_init(&tt_local->common.refcount); + kref_get(&tt_local->common.refcount); tt_local->last_seen = jiffies; tt_local->common.added_at = tt_local->last_seen;
@@ -1415,7 +1450,8 @@ static bool batadv_tt_global_add(struct batadv_priv *bat_priv, */ if (flags & BATADV_TT_CLIENT_ROAM) tt_global_entry->roam_at = jiffies; - atomic_set(&common->refcount, 2); + kref_init(&common->refcount); + kref_get(&common->refcount); common->added_at = jiffies;
INIT_HLIST_HEAD(&tt_global_entry->orig_list); diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index aea82a121c02..612de23178e6 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -972,7 +972,7 @@ struct batadv_tt_common_entry { struct hlist_node hash_entry; u16 flags; unsigned long added_at; - atomic_t refcount; + struct kref refcount; struct rcu_head rcu; };