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 | 26 +++++++++++++++++--------- net/batman-adv/types.h | 2 +- 2 files changed, 18 insertions(+), 10 deletions(-)
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index 0dc8a5ca33bf..68494a10848c 100644 --- 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 f89dd977f348..17f97ff5b4d1 100644 --- 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; };