From: Greg KH <gregkh@linuxfoundation.org>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>,
olaf@aepfle.de, jasowang@redhat.com,
linux-kernel@vger.kernel.org, apw@canonical.com,
devel@linuxdriverproject.org
Subject: Re: [PATCH 1/6] Drivers: hv: kvp: fix IP Failover
Date: Thu, 31 Mar 2016 13:19:02 -0700 [thread overview]
Message-ID: <20160331201902.GB22511@kroah.com> (raw)
In-Reply-To: <87y491tqor.fsf@vitty.brq.redhat.com>
On Tue, Mar 29, 2016 at 02:27:16PM +0200, Vitaly Kuznetsov wrote:
> "K. Y. Srinivasan" <kys@microsoft.com> writes:
>
> > 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>
>
> An issue was found with this patch: we don't cancel
> kvp_host_handshake_work on module unload and if the work is still
> pending we end up crashing. As far as I can see this series didn't make
> it to char-misc tree so instead of sending a patch to this patch I'll
> send v2 for the original issue.
>
> Sorry for the inconvenience.
Ok, I'll drop this whole series. K.Y., can you resend this series after
fixing this up?
thanks,
greg k-h
next prev parent reply other threads:[~2016-03-31 21:04 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-09 21:35 [PATCH 0/6] Drivers: hv: vmbus: Fix mmio management K. Y. Srinivasan
2016-03-09 21:35 ` [PATCH 1/6] Drivers: hv: kvp: fix IP Failover K. Y. Srinivasan
2016-03-09 21:35 ` [PATCH 2/6] hv: Make a function to free mmio regions through vmbus K. Y. Srinivasan
2016-03-09 21:35 ` [PATCH 3/6] hv: Lock access to hyperv_mmio resource tree K. Y. Srinivasan
2016-03-09 21:35 ` [PATCH 4/6] hv: Use new vmbus_mmio_free() from client drivers K. Y. Srinivasan
2016-03-09 21:35 ` [PATCH 5/6] hv: Reverse order of resources in hyperv_mmio K. Y. Srinivasan
2016-03-09 21:35 ` [PATCH 6/6] hv: Track allocations of children of hv_vmbus in private resource tree K. Y. Srinivasan
2016-03-29 12:27 ` [PATCH 1/6] Drivers: hv: kvp: fix IP Failover Vitaly Kuznetsov
2016-03-31 20:19 ` Greg KH [this message]
2016-04-01 21:03 ` KY Srinivasan
-- strict thread matches above, loose matches on Subject: below --
2016-04-02 18:10 [PATCH 0/6] Drivers: hv: vmbus: Cleanup and mmio management K. Y. Srinivasan
2016-04-02 18:10 ` [PATCH 1/6] Drivers: hv: kvp: fix IP Failover K. Y. Srinivasan
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