On Thu, Oct 15, 2026 at 04:43:33PM +0100, David Carlier wrote: > SO_INQ makes recvmsg() return the bytes left in the receive queue in an > SCM_INQ cmsg, saving a SIOCINQ call per receive. AF_UNIX stream sockets > support it, AF_VSOCK fails with ENOPROTOOPT. > > Add it for SOCK_STREAM, reusing the hint already computed for io_uring. > As with TCP_INQ, 1 is reported once the stream is finished so the caller > reads again and sees EOF, and accepted sockets inherit the setting from > the listener. No cmsg is sent when the transport cannot report the queue > length. > > SOCK_SEQPACKET is refused, as on AF_UNIX: its transport callback counts > messages, not bytes. > > Signed-off-by: David Carlier <[email protected]> > --- > include/net/af_vsock.h | 1 + > net/vmw_vsock/af_vsock.c | 111 +++++++++++++++++++++++++++++---------- > 2 files changed, 84 insertions(+), 28 deletions(-) > > diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h > index 5549298c1ec6..e8481f12312e 100644 > --- a/include/net/af_vsock.h > +++ b/include/net/af_vsock.h > @@ -68,6 +68,7 @@ struct vsock_sock { > u64 buffer_size; > u64 buffer_min_size; > u64 buffer_max_size; > + bool recvmsg_inq; > > /* Private to transport. */ > void *trans; > diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c > index 1c2d1cea67f4..186ed57fd797 100644 > --- a/net/vmw_vsock/af_vsock.c > +++ b/net/vmw_vsock/af_vsock.c > @@ -984,6 +984,7 @@ static struct sock *__vsock_create(struct net *net, > vsk->buffer_size = psk->buffer_size; > vsk->buffer_min_size = psk->buffer_min_size; > vsk->buffer_max_size = psk->buffer_max_size; > + vsk->recvmsg_inq = psk->recvmsg_inq; > security_sk_clone(parent, sk); > } else { > vsk->trusted = ns_capable_noaudit(&init_user_ns, CAP_NET_ADMIN); > @@ -2014,6 +2015,66 @@ static void vsock_update_buffer_size(struct vsock_sock > *vsk, > vsk->buffer_size = val; > } > > +static bool vsock_custom_sockopt(int optname) > +{ > + switch (optname) { > + case SO_ZEROCOPY: > + case SO_INQ: > + return true; > + default: > + return false; > + } > +} > + > +static int vsock_sol_socket_setsockopt(struct sock *sk, int optname, > + sockptr_t optval, unsigned int optlen) > +{ > + struct vsock_sock *vsk = vsock_sk(sk); > + int err = 0; > + int val; > + > + /* Use 'int' type here, because variable to > + * set these options usually has this type. > + */ > + if (optlen < sizeof(val)) > + return -EINVAL; > + > + if (copy_from_sockptr(&val, optval, sizeof(val))) > + return -EFAULT; > + > + if (val < 0 || val > 1) > + return -EINVAL; > + > + lock_sock(sk); > + > + switch (optname) { > + case SO_ZEROCOPY: > + if (vsk->transport && !vsock_msgzerocopy_allow(vsk->transport)) > { > + err = -EOPNOTSUPP; > + break; > + } > + > + sock_valbool_flag(sk, SOCK_ZEROCOPY, val); > + break; > + > + case SO_INQ: > + if (sk->sk_type != SOCK_STREAM) { > + err = -ENOPROTOOPT; > + break; > + } > + > + vsk->recvmsg_inq = val; > + break; > + > + default: > + err = -ENOPROTOOPT; > + break; > + } > + > + release_sock(sk); > + return err; > +} > + > static int vsock_connectible_setsockopt(struct socket *sock, > int level, > int optname, > @@ -2045,36 +2106,16 @@ static int vsock_connectible_setsockopt(struct socket > *sock, > sk = sock->sk; > vsk = vsock_sk(sk); > > - lock_sock(sk); > - > - transport = vsk->transport; > - > if (level == SOL_SOCKET) { > - int zerocopy; > - > - if (optname != SO_ZEROCOPY) { > - release_sock(sk); > + if (!vsock_custom_sockopt(optname)) > return sock_setsockopt(sock, level, optname, optval, > optlen); > - } > - > - /* Use 'int' type here, because variable to > - * set this option usually has this type. > - */ > - COPY_IN(zerocopy); > > - if (zerocopy < 0 || zerocopy > 1) { > - err = -EINVAL; > - goto exit; > - } > + return vsock_sol_socket_setsockopt(sk, optname, optval, optlen); > + } > > - if (transport && !vsock_msgzerocopy_allow(transport)) { > - err = -EOPNOTSUPP; > - goto exit; > - } > + lock_sock(sk); > > - sock_valbool_flag(sk, SOCK_ZEROCOPY, zerocopy); > - goto exit; > - } > + transport = vsk->transport; > > switch (optname) { > case SO_VM_SOCKETS_BUFFER_SIZE: > @@ -2581,6 +2622,7 @@ __vsock_connectible_recvmsg(struct socket *sock, struct > msghdr *msg, size_t len, > struct sock *sk; > struct vsock_sock *vsk; > const struct vsock_transport *transport; > + bool do_cmsg = false; > int err; > > sk = sock->sk; > @@ -2637,13 +2679,26 @@ __vsock_connectible_recvmsg(struct socket *sock, > struct msghdr *msg, size_t len, > err = __vsock_seqpacket_recvmsg(sk, msg, len, flags); > > out: > - /* Seqpacket has_data counts messages, while io_uring treats msg_inq as > - * a byte length when sizing retries, so only streams report a hint. > + /* Seqpacket has_data counts messages, while SCM_INQ reports bytes and > + * io_uring treats msg_inq as a byte length when sizing retries, so > + * only streams report it. > */ > - if (msg->msg_get_inq && err >= 0 && sk->sk_type == SOCK_STREAM) > + if ((vsk->recvmsg_inq || msg->msg_get_inq) && err >= 0 && > + sk->sk_type == SOCK_STREAM) { > msg->msg_inq = vsock_stream_inq_hint(sk); > > + /* A negative hint means the transport could not tell. SCM_INQ > + * has no encoding for that, so report nothing. > + */ > + do_cmsg = vsk->recvmsg_inq && msg->msg_inq >= 0; > + } > + > release_sock(sk); > + > + if (do_cmsg) > + put_cmsg(msg, SOL_SOCKET, SCM_INQ, sizeof(msg->msg_inq), > + &msg->msg_inq); > + > return err; > } > > -- > 2.55.0 >
All LGTM. Acked-by: Bobby Eshleman <[email protected]>
