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Message-ID: <20160430215409.GB4080@kroah.com>
Date: Sat, 30 Apr 2016 14:54:09 -0700
From: Greg KH <gregkh@...uxfoundation.org>
To: KY Srinivasan <kys@...rosoft.com>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"devel@...uxdriverproject.org" <devel@...uxdriverproject.org>,
"olaf@...fle.de" <olaf@...fle.de>,
"apw@...onical.com" <apw@...onical.com>,
"vkuznets@...hat.com" <vkuznets@...hat.com>,
"jasowang@...hat.com" <jasowang@...hat.com>
Subject: Re: [PATCH 1/8] Drivers: hv: kvp: fix IP Failover
On Sat, Apr 30, 2016 at 09:43:09PM +0000, KY Srinivasan wrote:
>
>
> > -----Original Message-----
> > From: Greg KH [mailto:gregkh@...uxfoundation.org]
> > Sent: Saturday, April 30, 2016 2:05 PM
> > To: KY Srinivasan <kys@...rosoft.com>
> > Cc: linux-kernel@...r.kernel.org; devel@...uxdriverproject.org;
> > olaf@...fle.de; apw@...onical.com; vkuznets@...hat.com;
> > jasowang@...hat.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@...hat.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@...hat.com>
> > > Signed-off-by: K. Y. Srinivasan <kys@...rosoft.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?
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