> -----Original Message-----
> From: Vitaly Kuznetsov [mailto:vkuzn...@redhat.com]
> Sent: Friday, March 17, 2017 9:16 AM
> To: Long Li <lon...@microsoft.com>
> Cc: KY Srinivasan <k...@microsoft.com>; Haiyang Zhang
> <haiya...@microsoft.com>; Stephen Hemminger
> <sthem...@microsoft.com>; de...@linuxdriverproject.org; linux-
> ker...@vger.kernel.org
> Subject: Re: [PATCH] HV: properly delay KVP packets when negotiation is in
> progress
>
> Long Li <lon...@microsoft.com> writes:
>
> > The host may send multiple KVP packets before the negotiation with
> > daemon is finished. We need to keep those packets in ring buffer until
> > the daemon is negotiated and connected.
>
> The patch looks OK but previously we always presumed that this can't
> happen for util drivers and host will never send a new request before we
> answer to the previous one. If this is not true we may have more issues
> which need fixing as all three drivers we have are written in a 'transaction'
> fashion.
>
> So my question would be: can the host send multiple (KVP) packets _after_
> the negotiation with daemon is finished?
Thanks Vitaly. I'm checking with Windows guys and will update soon.
>
>
> >
> > This patch is based on the work of Nick Meier
> > <nick.me...@microsoft.com>
> >
> > Signed-off-by: Long Li <lon...@microsoft.com>
> > ---
> > drivers/hv/hv_kvp.c | 9 +++++----
> > 1 file changed, 5 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c index
> > de26371..b9f928d 100644
> > --- a/drivers/hv/hv_kvp.c
> > +++ b/drivers/hv/hv_kvp.c
> > @@ -628,16 +628,17 @@ void hv_kvp_onchannelcallback(void *context)
> > NEGO_IN_PROGRESS,
> > NEGO_FINISHED} host_negotiatied =
> NEGO_NOT_STARTED;
> >
> > - if (host_negotiatied == NEGO_NOT_STARTED &&
> > - kvp_transaction.state < HVUTIL_READY) {
> > + if (kvp_transaction.state < HVUTIL_READY) {
> > /*
> > * If userspace daemon is not connected and host is asking
> > * us to negotiate we need to delay to not lose messages.
> > * This is important for Failover IP setting.
> > */
> > - host_negotiatied = NEGO_IN_PROGRESS;
> > - schedule_delayed_work(&kvp_host_handshake_work,
> > + if (host_negotiatied == NEGO_NOT_STARTED) {
> > + host_negotiatied = NEGO_IN_PROGRESS;
> > +
> schedule_delayed_work(&kvp_host_handshake_work,
> > HV_UTIL_NEGO_TIMEOUT * HZ);
> > + }
> > return;
> > }
> > if (kvp_transaction.state > HVUTIL_READY)
>
> --
> Vitaly
