The following commit has been merged in the master branch: commit 68a6722cc41f92ceffa8915bfe6a9c0307f2abeb Author: Sven Eckelmann sven@narfation.org Date: Sat Jan 16 10:29:47 2016 +0100

batman-adv: Convert batadv_dat_entry 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/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c index 017fffe..921e252 100644 --- a/net/batman-adv/distributed-arp-table.c +++ b/net/batman-adv/distributed-arp-table.c @@ -30,6 +30,7 @@ #include <linux/in.h> #include <linux/jiffies.h> #include <linux/kernel.h> +#include <linux/kref.h> #include <linux/list.h> #include <linux/rculist.h> #include <linux/rcupdate.h> @@ -62,14 +63,27 @@ static void batadv_dat_start_timer(struct batadv_priv *bat_priv) }

/** + * batadv_dat_entry_release - release dat_entry from lists and queue for free + * after rcu grace period + * @ref: kref pointer of the dat_entry + */ +static void batadv_dat_entry_release(struct kref *ref) +{ + struct batadv_dat_entry *dat_entry; + + dat_entry = container_of(ref, struct batadv_dat_entry, refcount); + + kfree_rcu(dat_entry, rcu); +} + +/** * batadv_dat_entry_free_ref - decrement the dat_entry refcounter and possibly - * free it - * @dat_entry: the entry to free + * release it + * @dat_entry: dat_entry to be free'd */ static void batadv_dat_entry_free_ref(struct batadv_dat_entry *dat_entry) { - if (atomic_dec_and_test(&dat_entry->refcount)) - kfree_rcu(dat_entry, rcu); + kref_put(&dat_entry->refcount, batadv_dat_entry_release); }

/** @@ -281,7 +295,7 @@ batadv_dat_entry_hash_find(struct batadv_priv *bat_priv, __be32 ip, if (dat_entry->ip != ip) continue;

- if (!atomic_inc_not_zero(&dat_entry->refcount)) + if (!kref_get_unless_zero(&dat_entry->refcount)) continue;

dat_entry_tmp = dat_entry; @@ -326,7 +340,8 @@ static void batadv_dat_entry_add(struct batadv_priv *bat_priv, __be32 ip, dat_entry->vid = vid; ether_addr_copy(dat_entry->mac_addr, mac_addr); dat_entry->last_update = jiffies; - atomic_set(&dat_entry->refcount, 2); + kref_init(&dat_entry->refcount); + kref_get(&dat_entry->refcount);

hash_added = batadv_hash_add(bat_priv->dat.hash, batadv_compare_dat, batadv_hash_dat, dat_entry, diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index b3d9b5b..9df8f39 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -1230,7 +1230,7 @@ struct batadv_dat_entry { unsigned short vid; unsigned long last_update; struct hlist_node hash_entry; - atomic_t refcount; + struct kref refcount; struct rcu_head rcu; };