batman-adv: Convert batadv_orig_ifinfo 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/routing.c b/net/batman-adv/routing.c
index 1c8b35d..4a5cd8b 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -25,6 +25,7 @@
 #include <linux/etherdevice.h>
 #include <linux/if_ether.h>
 #include <linux/jiffies.h>
+#include <linux/kref.h>
 #include <linux/netdevice.h>
 #include <linux/printk.h>
 #include <linux/rculist.h>
@@ -497,7 +498,7 @@
 
 	hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 		/* acquire some structures and references ... */
-		if (!atomic_inc_not_zero(&cand->refcount))
+		if (!kref_get_unless_zero(&cand->refcount))
 			continue;
 
 		cand_router = rcu_dereference(cand->router);
@@ -524,7 +525,7 @@
 		/* mark the first possible candidate */
 		if (!first_candidate) {
 			atomic_inc(&cand_router->refcount);
-			atomic_inc(&cand->refcount);
+			kref_get(&cand->refcount);
 			first_candidate = cand;
 			first_candidate_router = cand_router;
 		}