Re: [RFC PATCH v4 1/3] vsock: update SO_RCVLOWAT setting callback

[Stefano Garzarella]

On Thu, Nov 30, 2023 at 12:25:17AM +0300, Arseniy Krasnov wrote:
> Do not return if transport callback for SO_RCVLOWAT is set (only in
> error case). In this case we don't need to set 'sk_rcvlowat' field in
> each transport - only in 'vsock_set_rcvlowat()'. Also, if 'sk_rcvlowat'
> is now set only in af_vsock.c, change callback name from 'set_rcvlowat'
> to 'notify_set_rcvlowat'.
>
> Signed-off-by: Arseniy Krasnov <avkrasnov@xxxxxxxxxxxxxxxxx>
> ---
> Changelog:
> v3 -> v4:
>  * Rename 'set_rcvlowat' to 'notify_set_rcvlowat'.
>  * Commit message updated.

Reviewed-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>

> include/net/af_vsock.h           | 2 +-
> net/vmw_vsock/af_vsock.c         | 9 +++++++--
> net/vmw_vsock/hyperv_transport.c | 4 ++--
> 3 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
> index e302c0e804d0..535701efc1e5 100644
> --- a/include/net/af_vsock.h
> +++ b/include/net/af_vsock.h
> @@ -137,7 +137,6 @@ struct vsock_transport {
> 	u64 (*stream_rcvhiwat)(struct vsock_sock *);
> 	bool (*stream_is_active)(struct vsock_sock *);
> 	bool (*stream_allow)(u32 cid, u32 port);
> -	int (*set_rcvlowat)(struct vsock_sock *vsk, int val);
>
> 	/* SEQ_PACKET. */
> 	ssize_t (*seqpacket_dequeue)(struct vsock_sock *vsk, struct msghdr *msg,
> @@ -168,6 +167,7 @@ struct vsock_transport {
> 		struct vsock_transport_send_notify_data *);
> 	/* sk_lock held by the caller */
> 	void (*notify_buffer_size)(struct vsock_sock *, u64 *);
> +	int (*notify_set_rcvlowat)(struct vsock_sock *vsk, int val);
>
> 	/* Shutdown. */
> 	int (*shutdown)(struct vsock_sock *, int);
> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> index 816725af281f..54ba7316f808 100644
> --- a/net/vmw_vsock/af_vsock.c
> +++ b/net/vmw_vsock/af_vsock.c
> @@ -2264,8 +2264,13 @@ static int vsock_set_rcvlowat(struct sock *sk, int val)
>
> 	transport = vsk->transport;
>
> -	if (transport && transport->set_rcvlowat)
> -		return transport->set_rcvlowat(vsk, val);
> +	if (transport && transport->notify_set_rcvlowat) {
> +		int err;
> +
> +		err = transport->notify_set_rcvlowat(vsk, val);
> +		if (err)
> +			return err;
> +	}
>
> 	WRITE_ONCE(sk->sk_rcvlowat, val ? : 1);
> 	return 0;
> diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
> index 7cb1a9d2cdb4..e2157e387217 100644
> --- a/net/vmw_vsock/hyperv_transport.c
> +++ b/net/vmw_vsock/hyperv_transport.c
> @@ -816,7 +816,7 @@ int hvs_notify_send_post_enqueue(struct vsock_sock *vsk, ssize_t written,
> }
>
> static
> -int hvs_set_rcvlowat(struct vsock_sock *vsk, int val)
> +int hvs_notify_set_rcvlowat(struct vsock_sock *vsk, int val)
> {
> 	return -EOPNOTSUPP;
> }
> @@ -856,7 +856,7 @@ static struct vsock_transport hvs_transport = {
> 	.notify_send_pre_enqueue  = hvs_notify_send_pre_enqueue,
> 	.notify_send_post_enqueue = hvs_notify_send_post_enqueue,
>
> -	.set_rcvlowat             = hvs_set_rcvlowat
> +	.notify_set_rcvlowat      = hvs_notify_set_rcvlowat
> };
>
> static bool hvs_check_transport(struct vsock_sock *vsk)
> --
> 2.25.1