Virtualization - Jul 2022 - [RFC PATCH v1 2/3] virtio/vsock: use 'target' in notify_poll_in, callback.

On Wed, Jul 20, 2022 at 05:38:03AM +0000, Arseniy Krasnov
wrote:
>On 19.07.2022 15:48, Stefano Garzarella wrote:
>> On Mon, Jul 18, 2022 at 08:17:31AM +0000, Arseniy Krasnov wrote:
>>> This callback controls setting of POLLIN,POLLRDNORM output bits
>>> of poll() syscall,but in some cases,it is incorrectly to set it,
>>> when socket has at least 1 bytes of available data. Use
'target'
>>> which is already exists and equal to sk_rcvlowat in this case.
>>>
>>> Signed-off-by: Arseniy Krasnov <AVKrasnov at sberdevices.ru>
>>> ---
>>> net/vmw_vsock/virtio_transport_common.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/net/vmw_vsock/virtio_transport_common.c
b/net/vmw_vsock/virtio_transport_common.c
>>> index ec2c2afbf0d0..591908740992 100644
>>> --- a/net/vmw_vsock/virtio_transport_common.c
>>> +++ b/net/vmw_vsock/virtio_transport_common.c
>>> @@ -634,7 +634,7 @@ virtio_transport_notify_poll_in(struct
vsock_sock *vsk,
>>> ??????????????? size_t target,
>>> ??????????????? bool *data_ready_now)
>>> {
>>> -??? if (vsock_stream_has_data(vsk))
>>> +??? if (vsock_stream_has_data(vsk) >= target)
>>> ??????? *data_ready_now = true;
>>> ????else
>>> ??????? *data_ready_now = false;
>>
>> Perhaps we can take the opportunity to clean up the code in this way:
>>
>> ????*data_ready_now = vsock_stream_has_data(vsk) >= target;
>Ack
>>
>> Anyway, I think we also need to fix the other transports (vmci and
hyperv), what do you think?
>For vmci it is look clear to fix it. For hyperv i need to check it more,
because it already
>uses some internal target value.
Yep, I see. Maybe you can pass `target` to hvs_channel_readable() and 
use it as parameter of HVS_PKT_LEN().

@Dexuan what do you think?

Thanks,
Stefano