Re: [PATCH] can: add protocol counter for AF_CAN sockets

[Oliver Hartkopp <socketcan@hartkopp.net>]

Hello Davide,

thanks for your patch!

~/linux/net/can$ git grep sock_put .
af_can.c:               sock_put(sk);
af_can.c:               sock_put(sk);
bcm.c:  sock_put(sk);
isotp.c:        sock_put(sk);
j1939/socket.c: sock_put(sk);
j1939/transport.c:      sock_put(session->sk);
raw.c:  sock_put(sk);

But don't we need to take care on every place where sock_put() is called 
where sock_prot_inuse_add() has to decrease the counter?

Best regards,
Oliver

On 14.03.25 12:39, Davide Caratti wrote:
> 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>
> ---
>   net/can/af_can.c | 2 ++
>   net/can/bcm.c    | 1 +
>   net/can/isotp.c  | 1 +
>   net/can/raw.c    | 5 ++++-
>   4 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/net/can/af_can.c b/net/can/af_can.c
> index 01f3fbb3b67d..7b191dbe3693 100644
> --- a/net/can/af_can.c
> +++ b/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:
> diff --git a/net/can/bcm.c b/net/can/bcm.c
> index 217049fa496e..6dc041e054ba 100644
> --- a/net/can/bcm.c
> +++ b/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;
> diff --git a/net/can/isotp.c b/net/can/isotp.c
> index 16046931542a..789583c62f98 100644
> --- a/net/can/isotp.c
> +++ b/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;
> diff --git a/net/can/raw.c b/net/can/raw.c
> index 9b1d5f036f57..020f21430b1d 100644
> --- a/net/can/raw.c
> +++ b/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;