batman-adv: Convert batadv_softif_vlan to kref

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>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>

diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 4bf35b8..d4490ff 100644 (file)
--- 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 964fc59..ab4382b 100644 (file)
--- 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 06c3888..868f6b5 100644 (file)
--- 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;
 };