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

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Date:	Wed, 18 Sep 2013 16:04:11 +0000
From:	Paul Durrant <Paul.Durrant@...rix.com>
To:	Ian Campbell <Ian.Campbell@...rix.com>,
	Wei Liu <wei.liu2@...rix.com>
CC:	"xen-devel@...ts.xen.org" <xen-devel@...ts.xen.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	David Vrabel <david.vrabel@...rix.com>
Subject: RE: [PATCH net-next v4] Don't destroy the netdev until the vif is
 shut down

> -----Original Message-----
> From: Ian Campbell [mailto:ian.campbell@...rix.com]
> Sent: 18 September 2013 16:58
> To: Wei Liu
> Cc: Paul Durrant; xen-devel@...ts.xen.org; netdev@...r.kernel.org; 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@...rix.com>
> > > Cc: David Vrabel <david.vrabel@...rix.com>
> > > Cc: Wei Liu <wei.liu2@...rix.com>
> > > Cc: Ian Campbell <ian.campbell@...rix.com>
> >
> > Acked-by: Wei Liu <wei.liu2@...rix.com>
> 
> 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.

  Paul