net: af_netlink should update its inuse counter

In order to have relevant information for NETLINK protocol, in
/proc/net/protocols, we should use sock_prot_inuse_add() to
update a (percpu and pernamespace) counter of inuse sockets.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/netlink/af_netlink.c

@@ -452,6 +452,7 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol)
 	if (err < 0)
 		goto out_module;
 
+	sock_prot_inuse_add(net, &netlink_proto, 1);
 	nlk = nlk_sk(sock->sk);
 	nlk->module = module;
 out:
@@ -511,6 +512,7 @@ static int netlink_release(struct socket *sock)
 	kfree(nlk->groups);
 	nlk->groups = NULL;
 
+	sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
 	sock_put(sk);
 	return 0;
 }