nit: in theory in this patch we don't support it for any of the transports, so I wouldn't confuse and take that part out of the title.

WDYT with someting like:

    vsock: add support for SIOCOUTQ ioctl

On Wed, Jun 26, 2024 at 02:08:35PM GMT, Luigi Leonardi via B4 Relay wrote:
From: Luigi Leonardi <luigi.leona...@outlook.com>

Add support for ioctl(s) for SOCK_STREAM SOCK_SEQPACKET and SOCK_DGRAM
in AF_VSOCK.
The only ioctl available is SIOCOUTQ/TIOCOUTQ, which returns the number
of unsent bytes in the socket. This information is transport-specific
and is delegated to them using a callback.

Suggested-by: Daan De Meyer <daan.j.deme...@gmail.com>
Signed-off-by: Luigi Leonardi <luigi.leona...@outlook.com>
---
include/net/af_vsock.h   |  3 +++
net/vmw_vsock/af_vsock.c | 60 +++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 60 insertions(+), 3 deletions(-)

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 535701efc1e5..7b5375ae7827 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -169,6 +169,9 @@ struct vsock_transport {
        void (*notify_buffer_size)(struct vsock_sock *, u64 *);
        int (*notify_set_rcvlowat)(struct vsock_sock *vsk, int val);

+       /* SIOCOUTQ ioctl */
+       size_t (*unsent_bytes)(struct vsock_sock *vsk);

If you want to return also errors, maybe better returning ssize_t.
This should fix one of the error reported by kernel bots.

+
        /* Shutdown. */
        int (*shutdown)(struct vsock_sock *, int);

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 4b040285aa78..d6140d73d122 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -112,6 +112,7 @@
#include <net/sock.h>
#include <net/af_vsock.h>
#include <uapi/linux/vm_sockets.h>
+#include <uapi/asm-generic/ioctls.h>

static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr);
static void vsock_sk_destruct(struct sock *sk);
@@ -1292,6 +1293,59 @@ int vsock_dgram_recvmsg(struct socket *sock, struct 
msghdr *msg,
}
EXPORT_SYMBOL_GPL(vsock_dgram_recvmsg);

+static int vsock_do_ioctl(struct socket *sock, unsigned int cmd,
+                         int __user *arg)
+{
+       struct sock *sk = sock->sk;
+       struct vsock_sock *vsk;
+       int retval;
+
+       vsk = vsock_sk(sk);
+
+       switch (cmd) {
+       case SIOCOUTQ: {
+               size_t n_bytes;
+
+               if (!vsk->transport || !vsk->transport->unsent_bytes) {
+                       retval = -EOPNOTSUPP;
+                       break;
+               }
+
+               if (vsk->transport->unsent_bytes) {

This if is not necessary after the check we did earlier, right?

Removing it should fix the other issue reported by the bot.

+                       if (sock_type_connectible(sk->sk_type) && sk->sk_state 
== TCP_LISTEN) {
+                               retval = -EINVAL;
+                               break;
+                       }
+
+                       n_bytes = vsk->transport->unsent_bytes(vsk);
+                       if (n_bytes < 0) {
+                               retval = n_bytes;
+                               break;
+                       }
+
+                       retval = put_user(n_bytes, arg);
+               }
+               break;
+       }
+       default:
+               retval = -ENOIOCTLCMD;
+       }
+
+       return retval;
+}
+
+static int vsock_ioctl(struct socket *sock, unsigned int cmd,
+                      unsigned long arg)
+{
+       int ret;
+
+       lock_sock(sock->sk);
+       ret = vsock_do_ioctl(sock, cmd, (int __user *)arg);
+       release_sock(sock->sk);
+
+       return ret;
+}
+
static const struct proto_ops vsock_dgram_ops = {
        .family = PF_VSOCK,
        .owner = THIS_MODULE,
@@ -1302,7 +1356,7 @@ static const struct proto_ops vsock_dgram_ops = {
        .accept = sock_no_accept,
        .getname = vsock_getname,
        .poll = vsock_poll,
-       .ioctl = sock_no_ioctl,
+       .ioctl = vsock_ioctl,
        .listen = sock_no_listen,
        .shutdown = vsock_shutdown,
        .sendmsg = vsock_dgram_sendmsg,
@@ -2286,7 +2340,7 @@ static const struct proto_ops vsock_stream_ops = {
        .accept = vsock_accept,
        .getname = vsock_getname,
        .poll = vsock_poll,
-       .ioctl = sock_no_ioctl,
+       .ioctl = vsock_ioctl,
        .listen = vsock_listen,
        .shutdown = vsock_shutdown,
        .setsockopt = vsock_connectible_setsockopt,
@@ -2308,7 +2362,7 @@ static const struct proto_ops vsock_seqpacket_ops = {
        .accept = vsock_accept,
        .getname = vsock_getname,
        .poll = vsock_poll,
-       .ioctl = sock_no_ioctl,
+       .ioctl = vsock_ioctl,
        .listen = vsock_listen,
        .shutdown = vsock_shutdown,
        .setsockopt = vsock_connectible_setsockopt,

--
2.45.2





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