Re: [PATCH 1/8] Drivers: hv: kvp: fix IP Failover

[Greg KH <gregkh@linuxfoundation.org>]

On Sat, Apr 30, 2016 at 09:43:09PM +0000, KY Srinivasan wrote:
> 
> 
> > -----Original Message-----
> > From: Greg KH [mailto:gregkh@linuxfoundation.org]
> > Sent: Saturday, April 30, 2016 2:05 PM
> > To: KY Srinivasan <kys@microsoft.com>
> > Cc: linux-kernel@vger.kernel.org; devel@linuxdriverproject.org;
> > olaf@aepfle.de; apw@canonical.com; vkuznets@redhat.com;
> > jasowang@redhat.com
> > Subject: Re: [PATCH 1/8] Drivers: hv: kvp: fix IP Failover
> > 
> > On Tue, Apr 05, 2016 at 04:57:40PM -0700, K. Y. Srinivasan wrote:
> > > From: Vitaly Kuznetsov <vkuznets@redhat.com>
> > >
> > > Hyper-V VMs can be replicated to another hosts and there is a feature to
> > > set different IP for replicas, it is called 'Failover TCP/IP'. When
> > > such guest starts Hyper-V host sends it KVP_OP_SET_IP_INFO message as
> > soon
> > > as we finish negotiation procedure. The problem is that it can happen (and
> > > it actually happens) before userspace daemon connects and we reply with
> > > HV_E_FAIL to the message. As there are no repetitions we fail to set the
> > > requested IP.
> > >
> > > Solve the issue by postponing our reply to the negotiation message till
> > > userspace daemon is connected. We can't wait too long as there is a
> > > host-side timeout (cca. 75 seconds) and if we fail to reply in this time
> > > frame the whole KVP service will become inactive. The solution is not
> > > ideal - if it takes userspace daemon more than 60 seconds to connect
> > > IP Failover will still fail but I don't see a solution with our current
> > > separation between kernel and userspace parts.
> > >
> > > Other two modules (VSS and FCOPY) don't require such delay, leave them
> > > untouched.
> > >
> > > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> > > Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
> > > ---
> > >  drivers/hv/hv_kvp.c       |   31 +++++++++++++++++++++++++++++++
> > >  drivers/hv/hyperv_vmbus.h |    5 +++++
> > >  2 files changed, 36 insertions(+), 0 deletions(-)
> > 
> > This series doesn't apply to my tree :(
> 
> Looks like you have already applied most of the patches in this series. I will resend what is not applied.

If this was a "resend", why didn't it show that in the patch
description?