[v6,19/20] batman-adv: Convert batadv_tt_common_entry to kref
Commit Message
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/translation-table.c | 60 ++++++++++++++++++++++++++++++--------
net/batman-adv/types.h | 2 +-
2 files changed, 49 insertions(+), 13 deletions(-)
Comments
On Saturday, January 16, 2016 10:29:57 Sven Eckelmann wrote:
> 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/translation-table.c | 60
> ++++++++++++++++++++++++++++++--------
> net/batman-adv/types.h | 2 +-
> 2 files changed, 49 insertions(+), 13 deletions(-)
Applied in revision b81bdae.
Thanks,
Marek
@@ -142,7 +142,7 @@ batadv_tt_hash_find(struct batadv_hashtable *hash, const u8 *addr,
if (tt->vid != vid)
continue;
- if (!atomic_inc_not_zero(&tt->refcount))
+ if (!kref_get_unless_zero(&tt->refcount))
continue;
tt_tmp = tt;
@@ -203,25 +203,59 @@ batadv_tt_global_hash_find(struct batadv_priv *bat_priv, const u8 *addr,
return tt_global_entry;
}
+/**
+ * batadv_tt_local_entry_release - release tt_local_entry from lists and queue
+ * for free after rcu grace period
+ * @ref: kref pointer of the nc_node
+ */
+static void batadv_tt_local_entry_release(struct kref *ref)
+{
+ struct batadv_tt_local_entry *tt_local_entry;
+
+ tt_local_entry = container_of(ref, struct batadv_tt_local_entry,
+ common.refcount);
+
+ kfree_rcu(tt_local_entry, common.rcu);
+}
+
+/**
+ * batadv_tt_local_entry_free_ref - decrement the tt_local_entry refcounter and
+ * possibly release it
+ * @tt_local_entry: tt_local_entry to be free'd
+ */
static void
batadv_tt_local_entry_free_ref(struct batadv_tt_local_entry *tt_local_entry)
{
- if (atomic_dec_and_test(&tt_local_entry->common.refcount))
- kfree_rcu(tt_local_entry, common.rcu);
+ kref_put(&tt_local_entry->common.refcount,
+ batadv_tt_local_entry_release);
}
/**
- * batadv_tt_global_entry_free_ref - decrement the refcounter for a
- * tt_global_entry and possibly free it
- * @tt_global_entry: the object to free
+ * batadv_tt_global_entry_release - release tt_global_entry from lists and queue
+ * for free after rcu grace period
+ * @ref: kref pointer of the nc_node
+ */
+static void batadv_tt_global_entry_release(struct kref *ref)
+{
+ struct batadv_tt_global_entry *tt_global_entry;
+
+ tt_global_entry = container_of(ref, struct batadv_tt_global_entry,
+ common.refcount);
+
+ batadv_tt_global_del_orig_list(tt_global_entry);
+ kfree_rcu(tt_global_entry, common.rcu);
+}
+
+/**
+ * batadv_tt_global_entry_free_ref - decrement the tt_global_entry refcounter
+ * and possibly release it
+ * @tt_global_entry: tt_global_entry to be free'd
*/
static void
batadv_tt_global_entry_free_ref(struct batadv_tt_global_entry *tt_global_entry)
{
- if (atomic_dec_and_test(&tt_global_entry->common.refcount)) {
- batadv_tt_global_del_orig_list(tt_global_entry);
- kfree_rcu(tt_global_entry, common.rcu);
- }
+ kref_put(&tt_global_entry->common.refcount,
+ batadv_tt_global_entry_release);
}
/**
@@ -633,7 +667,8 @@ bool batadv_tt_local_add(struct net_device *soft_iface, const u8 *addr,
tt_local->common.vid = vid;
if (batadv_is_wifi_netdev(in_dev))
tt_local->common.flags |= BATADV_TT_CLIENT_WIFI;
- atomic_set(&tt_local->common.refcount, 2);
+ kref_init(&tt_local->common.refcount);
+ kref_get(&tt_local->common.refcount);
tt_local->last_seen = jiffies;
tt_local->common.added_at = tt_local->last_seen;
@@ -1415,7 +1450,8 @@ static bool batadv_tt_global_add(struct batadv_priv *bat_priv,
*/
if (flags & BATADV_TT_CLIENT_ROAM)
tt_global_entry->roam_at = jiffies;
- atomic_set(&common->refcount, 2);
+ kref_init(&common->refcount);
+ kref_get(&common->refcount);
common->added_at = jiffies;
INIT_HLIST_HEAD(&tt_global_entry->orig_list);
@@ -972,7 +972,7 @@ struct batadv_tt_common_entry {
struct hlist_node hash_entry;
u16 flags;
unsigned long added_at;
- atomic_t refcount;
+ struct kref refcount;
struct rcu_head rcu;
};