Re: [Xen-devel] [PATCH net-next v4] Don't destroy the netdev until the vif is shut down

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Ian Campbell [mailto:ian.campbell@xxxxxxxxxx]
> Sent: 18 September 2013 17:25
> To: Paul Durrant
> Cc: Wei Liu; xen-devel@xxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; David Vrabel
> Subject: Re: [PATCH net-next v4] Don't destroy the netdev until the vif is
> shut down
> 
> On Wed, 2013-09-18 at 17:04 +0100, Paul Durrant wrote:
> > > -----Original Message-----
> > > From: Ian Campbell [mailto:ian.campbell@xxxxxxxxxx]
> > > Sent: 18 September 2013 16:58
> > > To: Wei Liu
> > > Cc: Paul Durrant; xen-devel@xxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx;
> David
> > > Vrabel
> > > Subject: Re: [PATCH net-next v4] Don't destroy the netdev until the vif is
> > > shut down
> > >
> > > On Wed, 2013-09-18 at 11:37 +0100, Wei Liu wrote:
> > > > On Tue, Sep 17, 2013 at 05:46:08PM +0100, Paul Durrant wrote:
> > > > > Without this patch, if a frontend cycles through states Closing
> > > > > and Closed (which Windows frontends need to do) then the netdev
> > > > > will be destroyed and requires re-invocation of hotplug scripts
> > > > > to restore state before the frontend can move to Connected. Thus
> > > > > when udev is not in use the backend gets stuck in InitWait.
> > > > >
> > > > > With this patch, the netdev is left alone whilst the backend is
> > > > > still online and is only de-registered and freed just prior to
> > > > > destroying the vif (which is also nicely symmetrical with the
> > > > > netdev allocation and registration being done during probe) so
> > > > > no re-invocation of hotplug scripts is required.
> > > > >
> > > > > Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
> > > > > Cc: David Vrabel <david.vrabel@xxxxxxxxxx>
> > > > > Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
> > > > > Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
> > > >
> > > > Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> > >
> > > yeah, looks good, thanks.
> > >
> > > Paul, did you test this with non-Windows frontends too? and do things
> > > like vif hot(un)plug still work?
> > >
> >
> > Ian,
> >
> > I tested with a debian (wheezy) PV guest but I didn't test unplug. I
> > cycled a windows frontend several times (which is how I spotted the
> > tx_irq thing), and shutdown and brought up both the debian and windows
> > guests several times. I can test unplug too if you'd like.
> 
> I don't think it needs to be a blocker for accepting this patch but it
> would be good to try it, it's the sort of area which historically gets
> broken by this sort of change.
> 

FWIW I just checked network-detach with a windows frontend and it worked ok.

  Paul
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel