[B.A.T.M.A.N.] [PATCH v4 24/31] batman-adv: Convert batadv_neigh_ifinfo to kref

Sven Eckelmann
2016-01-05T11:06:39Z

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>
---
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/originator.c | 17 ++++++++++-------
net/batman-adv/types.h | 2 +-
2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 4517bc9..eb366c5 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -172,11 +172,14 @@ err:
/**
* batadv_neigh_ifinfo_release - release neigh_ifinfo from lists and queue for
* free after rcu grace period
- * @neigh_ifinfo: the neigh_ifinfo object to release
+ * @ref: kref pointer of the neigh_ifinfo
*/
-static void
-batadv_neigh_ifinfo_release(struct batadv_neigh_ifinfo *neigh_ifinfo)
+static void batadv_neigh_ifinfo_release(struct kref *ref)
{
+ struct batadv_neigh_ifinfo *neigh_ifinfo;
+
+ neigh_ifinfo = container_of(ref, struct batadv_neigh_ifinfo, refcount);
+
if (neigh_ifinfo->if_outgoing != BATADV_IF_DEFAULT)
batadv_hardif_free_ref(neigh_ifinfo->if_outgoing);

@@ -190,8 +193,7 @@ batadv_neigh_ifinfo_release(struct batadv_neigh_ifinfo *neigh_ifinfo)
*/
void batadv_neigh_ifinfo_free_ref(struct batadv_neigh_ifinfo *neigh_ifinfo)
{
- if (atomic_dec_and_test(&neigh_ifinfo->refcount))
- batadv_neigh_ifinfo_release(neigh_ifinfo);
+ kref_put(&neigh_ifinfo->refcount, batadv_neigh_ifinfo_release);
}

/**
@@ -405,7 +407,7 @@ batadv_neigh_ifinfo_get(struct batadv_neigh_node *neigh,
if (tmp_neigh_ifinfo->if_outgoing != if_outgoing)
continue;

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

neigh_ifinfo = tmp_neigh_ifinfo;
@@ -450,7 +452,8 @@ batadv_neigh_ifinfo_new(struct batadv_neigh_node *neigh,
}

INIT_HLIST_NODE(&neigh_ifinfo->list);
- atomic_set(&neigh_ifinfo->refcount, 2);
+ kref_init(&neigh_ifinfo->refcount);
+ kref_get(&neigh_ifinfo->refcount);
neigh_ifinfo->if_outgoing = if_outgoing;

hlist_add_head_rcu(&neigh_ifinfo->list, &neigh->ifinfo_list);
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 58ae09e..7831bf0 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -420,7 +420,7 @@ struct batadv_neigh_ifinfo {
struct batadv_hard_iface *if_outgoing;
struct batadv_neigh_ifinfo_bat_iv bat_iv;
u8 last_ttl;
- atomic_t refcount;
+ struct kref refcount;
struct rcu_head rcu;
};

--
2.6.4