can: add protocol counter for AF_CAN sockets

The third column in the output of the following command:

| # grep CAN /proc/net/protocols

is systematically '0': use sock_prot_inuse_add() to account for the number
of sockets for each protocol on top of AF_CAN family.

Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Link: https://patch.msgid.link/9db5d0e6c11b232ad895885616f1258882a32f61.1741952160.git.dcaratti@redhat.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

net/can/af_can.c

@@ -172,6 +172,8 @@ static int can_create(struct net *net, struct socket *sock, int protocol,
 		sock_orphan(sk);
 		sock_put(sk);
 		sock->sk = NULL;
+	} else {
+		sock_prot_inuse_add(net, sk->sk_prot, 1);
 	}
 
  errout:

net/can/bcm.c

@@ -1625,6 +1625,7 @@ static int bcm_release(struct socket *sock)
 	sock->sk = NULL;
 
 	release_sock(sk);
+	sock_prot_inuse_add(net, sk->sk_prot, -1);
 	sock_put(sk);
 
 	return 0;

net/can/isotp.c

@@ -1239,6 +1239,7 @@ static int isotp_release(struct socket *sock)
 	sock->sk = NULL;
 
 	release_sock(sk);
+	sock_prot_inuse_add(net, sk->sk_prot, -1);
 	sock_put(sk);
 
 	return 0;

net/can/raw.c

@@ -397,11 +397,13 @@ static int raw_release(struct socket *sock)
 {
 	struct sock *sk = sock->sk;
 	struct raw_sock *ro;
+	struct net *net;
 
 	if (!sk)
 		return 0;
 
 	ro = raw_sk(sk);
+	net = sock_net(sk);
 
 	spin_lock(&raw_notifier_lock);
 	while (raw_busy_notifier == ro) {
@@ -421,7 +423,7 @@ static int raw_release(struct socket *sock)
 			raw_disable_allfilters(dev_net(ro->dev), ro->dev, sk);
 			netdev_put(ro->dev, &ro->dev_tracker);
 		} else {
-			raw_disable_allfilters(sock_net(sk), NULL, sk);
+			raw_disable_allfilters(net, NULL, sk);
 		}
 	}
 
@@ -440,6 +442,7 @@ static int raw_release(struct socket *sock)
 	release_sock(sk);
 	rtnl_unlock();
 
+	sock_prot_inuse_add(net, sk->sk_prot, -1);
 	sock_put(sk);
 
 	return 0;