netfilter: cttimeout: inc/dec module refcount per object, not per use refcount

There is no need to increment the module refcount again, its enough to
obtain one reference per object, i.e. take a reference on object
creation and put it on object destruction.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nfnetlink_cttimeout.c

@@ -158,6 +158,7 @@ static int cttimeout_new_timeout(struct sk_buff *skb,
 	timeout->timeout.l3num = l3num;
 	timeout->timeout.l4proto = l4proto;
 	refcount_set(&timeout->refcnt, 1);
+	__module_get(THIS_MODULE);
 	list_add_tail_rcu(&timeout->head, &pernet->nfct_timeout_list);
 
 	return 0;
@@ -506,13 +507,8 @@ static struct nf_ct_timeout *ctnl_timeout_find_get(struct net *net,
 		if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
 			continue;
 
-		if (!try_module_get(THIS_MODULE))
+		if (!refcount_inc_not_zero(&timeout->refcnt))
 			goto err;
-
-		if (!refcount_inc_not_zero(&timeout->refcnt)) {
-			module_put(THIS_MODULE);
-			goto err;
-		}
 		matching = timeout;
 		break;
 	}
@@ -525,10 +521,10 @@ static void ctnl_timeout_put(struct nf_ct_timeout *t)
 	struct ctnl_timeout *timeout =
 		container_of(t, struct ctnl_timeout, timeout);
 
-	if (refcount_dec_and_test(&timeout->refcnt))
+	if (refcount_dec_and_test(&timeout->refcnt)) {
 		kfree_rcu(timeout, rcu_head);
-
-	module_put(THIS_MODULE);
+		module_put(THIS_MODULE);
+	}
 }
 
 static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = {