bpf, vsock: Fix poll() missing a queue

When a verdict program simply passes a packet without redirection, sk_msg
is enqueued on sk_psock::ingress_msg. Add a missing check to poll().

Fixes: 634f1a7 ("vsock: support sockmap")
Signed-off-by: Michal Luczaj <[email protected]>
Reviewed-by: Stefano Garzarella <[email protected]>
Reviewed-by: Luigi Leonardi <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: John Fastabend <[email protected]>

Author: mmhal

net/vmw_vsock/af_vsock.c

@@ -1054,6 +1054,9 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
 		mask |= EPOLLRDHUP;
 	}
 
+	if (sk_is_readable(sk))
+		mask |= EPOLLIN | EPOLLRDNORM;
+
 	if (sock->type == SOCK_DGRAM) {
 		/* For datagram sockets we can read if there is something in
 		 * the queue and write as long as the socket isn't shutdown for