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/soft-interface.c | 33 +++++++++++++++++++++++---------- net/batman-adv/sysfs.c | 3 ++- net/batman-adv/types.h | 2 +- 3 files changed, 26 insertions(+), 12 deletions(-)
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index 6c65de9..4b55b5f 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -30,6 +30,7 @@ #include <linux/if_vlan.h> #include <linux/jiffies.h> #include <linux/kernel.h> +#include <linux/kref.h> #include <linux/list.h> #include <linux/lockdep.h> #include <linux/netdevice.h> @@ -478,8 +479,26 @@ out: }
/** + * batadv_softif_vlan_release - release vlan from lists and queue for free after + * rcu grace period + * @ref: kref pointer of the vlan object + */ +static void batadv_softif_vlan_release(struct kref *ref) +{ + struct batadv_softif_vlan *vlan; + + vlan = container_of(ref, struct batadv_softif_vlan, refcount); + + spin_lock_bh(&vlan->bat_priv->softif_vlan_list_lock); + hlist_del_rcu(&vlan->list); + spin_unlock_bh(&vlan->bat_priv->softif_vlan_list_lock); + + kfree_rcu(vlan, rcu); +} + +/** * batadv_softif_vlan_free_ref - decrease the vlan object refcounter and - * possibly free it + * possibly release it * @vlan: the vlan object to release */ void batadv_softif_vlan_free_ref(struct batadv_softif_vlan *vlan) @@ -487,13 +506,7 @@ void batadv_softif_vlan_free_ref(struct batadv_softif_vlan *vlan) if (!vlan) return;
- if (atomic_dec_and_test(&vlan->refcount)) { - spin_lock_bh(&vlan->bat_priv->softif_vlan_list_lock); - hlist_del_rcu(&vlan->list); - spin_unlock_bh(&vlan->bat_priv->softif_vlan_list_lock); - - kfree_rcu(vlan, rcu); - } + kref_put(&vlan->refcount, batadv_softif_vlan_release); }
/** @@ -514,7 +527,7 @@ struct batadv_softif_vlan *batadv_softif_vlan_get(struct batadv_priv *bat_priv, if (vlan_tmp->vid != vid) continue;
- if (!atomic_inc_not_zero(&vlan_tmp->refcount)) + if (!kref_get_unless_zero(&vlan_tmp->refcount)) continue;
vlan = vlan_tmp; @@ -549,7 +562,7 @@ int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid)
vlan->bat_priv = bat_priv; vlan->vid = vid; - atomic_set(&vlan->refcount, 1); + kref_init(&vlan->refcount);
atomic_set(&vlan->ap_isolation, 0);
diff --git a/net/batman-adv/sysfs.c b/net/batman-adv/sysfs.c index f38d7b7..4f578ac 100644 --- a/net/batman-adv/sysfs.c +++ b/net/batman-adv/sysfs.c @@ -25,6 +25,7 @@ #include <linux/fs.h> #include <linux/if.h> #include <linux/if_vlan.h> +#include <linux/kref.h> #include <linux/kernel.h> #include <linux/netdevice.h> #include <linux/printk.h> @@ -97,7 +98,7 @@ batadv_kobj_to_vlan(struct batadv_priv *bat_priv, struct kobject *obj) if (vlan_tmp->kobj != obj) continue;
- if (!atomic_inc_not_zero(&vlan_tmp->refcount)) + if (!kref_get_unless_zero(&vlan_tmp->refcount)) continue;
vlan = vlan_tmp; diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 0b3cbdb..c6c3f0f 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -746,7 +746,7 @@ struct batadv_softif_vlan { atomic_t ap_isolation; /* boolean */ struct batadv_vlan_tt tt; struct hlist_node list; - atomic_t refcount; + struct kref refcount; struct rcu_head rcu; };