batman-adv: Convert batadv_hard_iface 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>

1 files changed, 13 insertions, 7 deletions

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index b17e272b5cb3..fb2d9c058ed0 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -18,6 +18,7 @@
 #include "hard-interface.h"
 #include "main.h"
 
+#include <linux/atomic.h>
 #include <linux/bug.h>
 #include <linux/byteorder/generic.h>
 #include <linux/errno.h>
@@ -26,6 +27,7 @@
 #include <linux/if_ether.h>
 #include <linux/if.h>
 #include <linux/kernel.h>
+#include <linux/kref.h>
 #include <linux/list.h>
 #include <linux/netdevice.h>
 #include <linux/printk.h>
@@ -50,10 +52,13 @@
 /**
  * batadv_hardif_release - release hard interface from lists and queue for
  *  free after rcu grace period
- * @hard_iface: the hard interface to free
+ * @ref: kref pointer of the hard interface
  */
-void batadv_hardif_release(struct batadv_hard_iface *hard_iface)
+void batadv_hardif_release(struct kref *ref)
 {
+	struct batadv_hard_iface *hard_iface;
+
+	hard_iface = container_of(ref, struct batadv_hard_iface, refcount);
 	dev_put(hard_iface->net_dev);
 
 	kfree_rcu(hard_iface, rcu);
@@ -67,7 +72,7 @@ batadv_hardif_get_by_netdev(const struct net_device *net_dev)
 	rcu_read_lock();
 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 		if (hard_iface->net_dev == net_dev &&
-		    atomic_inc_not_zero(&hard_iface->refcount))
+		    kref_get_unless_zero(&hard_iface->refcount))
 			goto out;
 	}
 
@@ -172,7 +177,7 @@ batadv_hardif_get_active(const struct net_device *soft_iface)
 			continue;
 
 		if (hard_iface->if_status == BATADV_IF_ACTIVE &&
-		    atomic_inc_not_zero(&hard_iface->refcount))
+		    kref_get_unless_zero(&hard_iface->refcount))
 			goto out;
 	}
 
@@ -206,7 +211,7 @@ static void batadv_primary_if_select(struct batadv_priv *bat_priv,
 
 	ASSERT_RTNL();
 
-	if (new_hard_iface && !atomic_inc_not_zero(&new_hard_iface->refcount))
+	if (new_hard_iface && !kref_get_unless_zero(&new_hard_iface->refcount))
 		new_hard_iface = NULL;
 
 	curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
@@ -434,7 +439,7 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
 	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 		goto out;
 
-	if (!atomic_inc_not_zero(&hard_iface->refcount))
+	if (!kref_get_unless_zero(&hard_iface->refcount))
 		goto out;
 
 	soft_iface = dev_get_by_name(&init_net, iface_name);
@@ -655,7 +660,8 @@ batadv_hardif_add_interface(struct net_device *net_dev)
 		hard_iface->num_bcasts = BATADV_NUM_BCASTS_WIRELESS;
 
 	/* extra reference for return */
-	atomic_set(&hard_iface->refcount, 2);
+	kref_init(&hard_iface->refcount);
+	kref_get(&hard_iface->refcount);
 
 	batadv_check_known_mac_addr(hard_iface->net_dev);
 	list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);