afkey: add sparse annotation about rcu

Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/key/af_key.c

@@ -3655,6 +3655,7 @@ static int pfkey_seq_show(struct seq_file *f, void *v)
 }
 
 static void *pfkey_seq_start(struct seq_file *f, loff_t *ppos)
+	__acquires(rcu)
 {
 	struct net *net = seq_file_net(f);
 	struct netns_pfkey *net_pfkey = net_generic(net, pfkey_net_id);
@@ -3672,6 +3673,7 @@ static void *pfkey_seq_next(struct seq_file *f, void *v, loff_t *ppos)
 }
 
 static void pfkey_seq_stop(struct seq_file *f, void *v)
+	__releases(rcu)
 {
 	rcu_read_unlock();
 }