When hv_sock was originally added, __vsock_stream_recvmsg() and vsock_stream_has_data() actually only needed to know whether there is any readable data or not, so hvs_stream_has_data() was written to return 1 or 0 for simplicity. However, now hvs_stream_has_data() should return the readable bytes because vsock_data_ready() -> vsock_stream_has_data() needs to know the actual bytes rather than a boolean value of 1 or 0. The SIOCINQ ioctl support also needs hvs_stream_has_data() to return the readable bytes. Let hvs_stream_has_data() return the readable bytes of the payload in the next host-to-guest VMBus hv_sock packet. Note: there may be multpile incoming hv_sock packets pending in the VMBus channel's ringbuffer, but so far there is not a VMBus API that allows us to know all the readable bytes in total without reading and caching the payload of the multiple packets, so let's just return the readable bytes of the next single packet. In the future, we'll either add a VMBus API that allows us to know the total readable bytes without touching the data in the ringbuffer, or the hv_sock driver needs to understand the VMBus packet format and parse the packets directly. Signed-off-by: Dexuan Cui --- net/vmw_vsock/hyperv_transport.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c index 31342ab502b4fc35feb812d2c94e0e35ded73771..432fcbbd14d4f44bd2550be8376e42ce65122758 100644 --- a/net/vmw_vsock/hyperv_transport.c +++ b/net/vmw_vsock/hyperv_transport.c @@ -694,15 +694,26 @@ static ssize_t hvs_stream_enqueue(struct vsock_sock *vsk, struct msghdr *msg, static s64 hvs_stream_has_data(struct vsock_sock *vsk) { struct hvsock *hvs = vsk->trans; + bool need_refill; s64 ret; if (hvs->recv_data_len > 0) - return 1; + return hvs->recv_data_len; switch (hvs_channel_readable_payload(hvs->chan)) { case 1: - ret = 1; - break; + need_refill = !hvs->recv_desc; + if (!need_refill) + return -EIO; + + hvs->recv_desc = hv_pkt_iter_first(hvs->chan); + if (!hvs->recv_desc) + return -ENOBUFS; + + ret = hvs_update_recv_data(hvs); + if (ret) + return ret; + return hvs->recv_data_len; case 0: vsk->peer_shutdown |= SEND_SHUTDOWN; ret = 0; -- 2.34.1