[B.A.T.M.A.N.] [PATCH v4 21/31] batman-adv: Convert batadv_tvlv_container to kref

Sven Eckelmann
2016-01-05T11:06:36Z

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/main.c | 22 +++++++++++++++++-----
net/batman-adv/types.h | 2 +-
2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index 9d34be6..476890e 100644
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -29,6 +29,7 @@
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/kernel.h>
+#include <linux/kref.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/module.h>
@@ -670,14 +671,25 @@ static struct batadv_tvlv_handler
}

/**
+ * batadv_tvlv_container_release - release tvlv from lists and free
+ * @ref: kref pointer of the tvlv
+ */
+static void batadv_tvlv_container_release(struct kref *ref)
+{
+ struct batadv_tvlv_container *tvlv;
+
+ tvlv = container_of(ref, struct batadv_tvlv_container, refcount);
+ kfree(tvlv);
+}
+
+/**
* batadv_tvlv_container_free_ref - decrement the tvlv container refcounter and
- * possibly free it
+ * possibly release it
* @tvlv: the tvlv container to free
*/
static void batadv_tvlv_container_free_ref(struct batadv_tvlv_container *tvlv)
{
- if (atomic_dec_and_test(&tvlv->refcount))
- kfree(tvlv);
+ kref_put(&tvlv->refcount, batadv_tvlv_container_release);
}

/**
@@ -704,7 +716,7 @@ static struct batadv_tvlv_container
if (tvlv_tmp->tvlv_hdr.version != version)
continue;

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

tvlv = tvlv_tmp;
@@ -810,7 +822,7 @@ void batadv_tvlv_container_register(struct batadv_priv *bat_priv,

memcpy(tvlv_new + 1, tvlv_value, ntohs(tvlv_new->tvlv_hdr.len));
INIT_HLIST_NODE(&tvlv_new->list);
- atomic_set(&tvlv_new->refcount, 1);
+ kref_init(&tvlv_new->refcount);

spin_lock_bh(&bat_priv->tvlv.container_list_lock);
tvlv_old = batadv_tvlv_container_get(bat_priv, type, version);
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index a6ba6c0..0ebd5a4 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -1266,7 +1266,7 @@ struct batadv_dat_candidate {
struct batadv_tvlv_container {
struct hlist_node list;
struct batadv_tvlv_hdr tvlv_hdr;
- atomic_t refcount;
+ struct kref refcount;
};

/**
--
2.6.4