Re: [PATCH v6 06/11] qapi: add failover negotiated event

[Michael S. Tsirkin]

On Fri, Oct 25, 2019 at 07:39:21PM +0200, Jens Freimann wrote:
> On Fri, Oct 25, 2019 at 04:03:54PM +0200, Markus Armbruster wrote:
> > Bear with me, I know next to nothing about failover.
> > 
> > Jens Freimann <address@hidden> writes:
> > 
> > > This event is sent to let libvirt know that VIRTIO_NET_F_STANDBY feature
> > > was enabled. The primary device this virtio-net device is associated
> > > with, will now be hotplugged via qdev_device_add().
> > 
> > Passive voice deftly avoids telling the reader who will do the
> > hot-plugging.  Intentional?
> 
> Not really, it's in the comment to the event. The hotplug will be
> done by the virtio-net device code that activates the feature, in
> virtio_net_set_features().
> 
> > 
> > > Signed-off-by: Jens Freimann <address@hidden>
> > > Acked-by: Cornelia Huck <address@hidden>
> > > ---
> > >  qapi/net.json | 19 +++++++++++++++++++
> > >  1 file changed, 19 insertions(+)
> > > 
> > > diff --git a/qapi/net.json b/qapi/net.json
> > > index 728990f4fb..ea6eeee4f7 100644
> > > --- a/qapi/net.json
> > > +++ b/qapi/net.json
> > > @@ -737,3 +737,22 @@
> > >  ##
> > >  { 'command': 'announce-self', 'boxed': true,
> > >    'data' : 'AnnounceParameters'}
> > > +
> > > +##
> > > +# @FAILOVER_NEGOTIATED:
> > > +#
> > > +# Emitted when VIRTIO_NET_F_STANDBY was enabled during feature 
> > > negotiation.
> > > +# Failover primary devices which were hidden (not hotplugged when 
> > > requested)
> > > +# before will now be hotplugged by the virtio-net standby device.
> > > +#
> > > +# device-id: QEMU device id of the unplugged device
> > 
> > @device-id is new since v5.
> > 
> > A quick skim of
> > https://www.kernel.org/doc/html/latest/networking/net_failover.html
> > tells me there are three devices involved: master, primary slave,
> > standby slave.  Which one is @device-id?  Or am I confused?
> 
> Yes, the device-id is new and it's the device-id of the standby (i.e.
> virtio-net) device.
> 
> regards,
> Jens

And now I am confused.
How is standby "the unplugged device"?
Why not just say "the standby device"?

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MST