Re: [PATCH net-next v3 1/3] vsock: Add support for SIOCINQ ioctl

[Stefano Garzarella]

CCin hyper-v maintainers and list since I have a question about hyperv 
transport.

On Tue, Jun 17, 2025 at 12:53:44PM +0800, Xuewei Niu wrote:
> Add support for SIOCINQ ioctl, indicating the length of bytes unread in the
> socket. The value is obtained from `vsock_stream_has_data()`.
>
> Signed-off-by: Xuewei Niu <niuxuewei.nxw@xxxxxxxxxxxx>
> ---
> net/vmw_vsock/af_vsock.c | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> index 2e7a3034e965..bae6b89bb5fb 100644
> --- a/net/vmw_vsock/af_vsock.c
> +++ b/net/vmw_vsock/af_vsock.c
> @@ -1389,6 +1389,28 @@ static int vsock_do_ioctl(struct socket *sock, unsigned int cmd,
> 	vsk = vsock_sk(sk);
>
> 	switch (cmd) {
> +	case SIOCINQ: {
> +		ssize_t n_bytes;
> +
> +		if (!vsk->transport) {
> +			ret = -EOPNOTSUPP;
> +			break;
> +		}
> +
> +		if (sock_type_connectible(sk->sk_type) &&
> +		    sk->sk_state == TCP_LISTEN) {
> +			ret = -EINVAL;
> +			break;
> +		}
> +
> +		n_bytes = vsock_stream_has_data(vsk);

Now looks better to me, I just checked transports: vmci and virtio/vhost 
returns what we want, but for hyperv we have:

	static s64 hvs_stream_has_data(struct vsock_sock *vsk)
	{
		struct hvsock *hvs = vsk->trans;
		s64 ret;

		if (hvs->recv_data_len > 0)
			return 1;

@Hyper-v maintainers: do you know why we don't return `recv_data_len`?
Do you think we can do that to support this new feature?

Thanks,
Stefano

> +		if (n_bytes < 0) {
> +			ret = n_bytes;
> +			break;
> +		}
> +		ret = put_user(n_bytes, arg);
> +		break;
> +	}
> 	case SIOCOUTQ: {
> 		ssize_t n_bytes;
>
> --
> 2.34.1