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@antgroup.com>
---
 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 2e7a3034e965db30b6ee295370d866e6d8b1c341..bae6b89bb5fb7dd7a3a378f92097561a98a0c814 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);
+		if (n_bytes < 0) {
+			ret = n_bytes;
+			break;
+		}
+		ret = put_user(n_bytes, arg);
+		break;
+	}
 	case SIOCOUTQ: {
 		ssize_t n_bytes;
 

-- 
2.34.1