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

-----Original Message-----
From: Ian Campbell [mailto:ian.campbell@citrix.com]
Sent: 18 September 2013 17:25
To: Paul Durrant
Cc: Wei Liu; xen-devel@lists.xen.org; netdev@vger.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 17:04 +0100, Paul Durrant wrote:

quoted

quoted

-----Original Message-----
From: Ian Campbell [mailto:ian.campbell@citrix.com]
Sent: 18 September 2013 16:58
To: Wei Liu
Cc: Paul Durrant; xen-devel@lists.xen.org; netdev@vger.kernel.org;

David

quoted

quoted

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:

quoted

On Tue, Sep 17, 2013 at 05:46:08PM +0100, Paul Durrant wrote:

quoted

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 <redacted>
Cc: David Vrabel <redacted>
Cc: Wei Liu <redacted>
Cc: Ian Campbell <redacted>

Acked-by: Wei Liu <redacted>

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