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 --- v6: - removed patches which are now applied in the branch next - rebased remaining patches on the patch "batman-adv: Avoid recursive call_rcu for batadv_nc_node" which was modified by Marek while he applied the patches (this unfortunately made some of the remaining patches "hard" to apply) v5: - add hack which allows to compile against stable kernel like 3.2.44 which also added the kref_get_unless_zero function v4: - fix function names in commit messages - fix double whitespace in batadv_tt_orig_list_entry_release kerneldoc - add extra patch for batadv_claim_free_ref kerneldoc fix - change the phrase "free it" in all *_free_ref/*_put functions to "release it" v3: - update copyright year v2: - split patchset into fixes and kref migration to make it easier when the decision is made where each patch will be applied
net/batman-adv/network-coding.c | 28 +++++++++++++++++++++------- net/batman-adv/types.h | 2 +- 2 files changed, 22 insertions(+), 8 deletions(-)
diff --git a/net/batman-adv/network-coding.c b/net/batman-adv/network-coding.c index 7a1216e..371fc6b 100644 --- a/net/batman-adv/network-coding.c +++ b/net/batman-adv/network-coding.c @@ -233,14 +233,27 @@ static void batadv_nc_node_free_ref(struct batadv_nc_node *nc_node) }
/** - * batadv_nc_path_free_ref - decrements the nc path refcounter and possibly - * frees it - * @nc_path: the nc node to free + * batadv_nc_path_release - release nc_path from lists and queue for free after + * rcu grace period + * @ref: kref pointer of the nc_path + */ +static void batadv_nc_path_release(struct kref *ref) +{ + struct batadv_nc_path *nc_path; + + nc_path = container_of(ref, struct batadv_nc_path, refcount); + + kfree_rcu(nc_path, rcu); +} + +/** + * batadv_nc_path_free_ref - decrement the nc_path refcounter and possibly + * release it + * @nc_path: nc_path to be free'd */ static void batadv_nc_path_free_ref(struct batadv_nc_path *nc_path) { - if (atomic_dec_and_test(&nc_path->refcount)) - kfree_rcu(nc_path, rcu); + kref_put(&nc_path->refcount, batadv_nc_path_release); }
/** @@ -545,7 +558,7 @@ batadv_nc_hash_find(struct batadv_hashtable *hash, if (!batadv_nc_hash_compare(&nc_path->hash_entry, data)) continue;
- if (!atomic_inc_not_zero(&nc_path->refcount)) + if (!kref_get_unless_zero(&nc_path->refcount)) continue;
nc_path_tmp = nc_path; @@ -972,7 +985,8 @@ static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv, /* Initialize nc_path */ INIT_LIST_HEAD(&nc_path->packet_list); spin_lock_init(&nc_path->packet_list_lock); - atomic_set(&nc_path->refcount, 2); + kref_init(&nc_path->refcount); + kref_get(&nc_path->refcount); nc_path->last_valid = jiffies; ether_addr_copy(nc_path->next_hop, dst); ether_addr_copy(nc_path->prev_hop, src); diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 05421af..b3d9b5b 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -1087,7 +1087,7 @@ struct batadv_nc_node { struct batadv_nc_path { struct hlist_node hash_entry; struct rcu_head rcu; - atomic_t refcount; + struct kref refcount; struct list_head packet_list; spinlock_t packet_list_lock; /* Protects packet_list */ u8 next_hop[ETH_ALEN];