[v6,17/20] batman-adv: Convert batadv_orig_node_vlan 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/originator.c | 26 ++++++++++++++++++++------
net/batman-adv/types.h | 2 +-
2 files changed, 21 insertions(+), 7 deletions(-)
Comments
On Saturday, January 16, 2016 10:29:55 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/originator.c | 26 ++++++++++++++++++++------
> net/batman-adv/types.h | 2 +-
> 2 files changed, 21 insertions(+), 7 deletions(-)
Applied in revision 33b1d7c.
Thanks,
Marek
@@ -82,7 +82,7 @@ batadv_orig_node_vlan_get(struct batadv_orig_node *orig_node,
if (tmp->vid != vid)
continue;
- if (!atomic_inc_not_zero(&tmp->refcount))
+ if (!kref_get_unless_zero(&tmp->refcount))
continue;
vlan = tmp;
@@ -123,7 +123,8 @@ batadv_orig_node_vlan_new(struct batadv_orig_node *orig_node,
if (!vlan)
goto out;
- atomic_set(&vlan->refcount, 2);
+ kref_init(&vlan->refcount);
+ kref_get(&vlan->refcount);
vlan->vid = vid;
hlist_add_head_rcu(&vlan->list, &orig_node->vlan_list);
@@ -135,14 +136,27 @@ out:
}
/**
- * batadv_orig_node_vlan_free_ref - decrement the refcounter and possibly free
- * the originator-vlan object
+ * batadv_orig_node_vlan_release - release originator-vlan object from lists
+ * and queue for free after rcu grace period
+ * @ref: kref pointer of the originator-vlan object
+ */
+static void batadv_orig_node_vlan_release(struct kref *ref)
+{
+ struct batadv_orig_node_vlan *orig_vlan;
+
+ orig_vlan = container_of(ref, struct batadv_orig_node_vlan, refcount);
+
+ kfree_rcu(orig_vlan, rcu);
+}
+
+/**
+ * batadv_orig_node_vlan_free_ref - decrement the refcounter and possibly
+ * release the originator-vlan object
* @orig_vlan: the originator-vlan object to release
*/
void batadv_orig_node_vlan_free_ref(struct batadv_orig_node_vlan *orig_vlan)
{
- if (atomic_dec_and_test(&orig_vlan->refcount))
- kfree_rcu(orig_vlan, rcu);
+ kref_put(&orig_vlan->refcount, batadv_orig_node_vlan_release);
}
int batadv_originator_init(struct batadv_priv *bat_priv)
@@ -197,7 +197,7 @@ struct batadv_orig_node_vlan {
unsigned short vid;
struct batadv_vlan_tt tt;
struct hlist_node list;
- atomic_t refcount;
+ struct kref refcount;
struct rcu_head rcu;
};