Re: [RFC PATCH v1 2/3] virtio/vsock: use 'target' in notify_poll_in, callback.

[Stefano Garzarella]

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@xxxxxxxxxxxxxx>
> > > ---
> > > 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