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(-)
diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c index bf27007..8b2ef8d 100644 --- a/net/batman-adv/originator.c +++ b/net/batman-adv/originator.c @@ -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) diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 74cb263..504f3db 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -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; };