Subject: Re: [PATCH net] failover: eliminate callback hell

From: Stephen Hemminger <[email-masked]>
Date: Wed, 6 Jun 2018 14:17:16 -0700

On Wed, 6 Jun 2018 15:19:30 +0300
"Michael S. Tsirkin" <[email-masked]> wrote:

> On Tue, Jun 05, 2018 at 08:51:18PM -0700, Stephen Hemminger wrote:
> > > I think the push back was with the usage of the delay, not bringing up the primary/standby
> > > device in the name change event handler.
> > > Can't netvsc use this mechanism instead of depending on the delay?
> > > 
> > >   
> > 
> > The patch that was rejected for netvsc was about using name change.  
> 
> So failover is now doing exactly what you wanted netvsc to do.  Rather
> than reverting everyone to old behaviour how about using more pieces
> from failover?
> 
> > Also, you can't depend on name change; you still need a timer. Not all distributions
> > change name of devices.  
> 
> So failover chose not to implement the delayed open so far.
> If it does I suspect we'll have to keep it around forever -
> kind of like netvsc seems to be stuck with it.
> But let's see if there's enough actual demand from people running
> ancient distros with latest kernels to even start looking for
> a solution for failover.
> 
> And this kind of behaviour change really should be split out
> so we can discuss it separately.
> 
> > Or user has blocked that by udev rules.  
> 
> Don't do that then?
> 

If you don't want to allow udev to rename the device, then just pull
the name change hook.