Re: [PATCH] ethtool: ETHTOOL_SFEATURES: remove NETIF_F_COMPAT return

[Ben Hutchings <bhutchings@solarflare.com>]

On Tue, 2011-05-24 at 23:59 +0200, Michał Mirosław wrote:
> On Tue, May 24, 2011 at 03:39:30PM -0400, David Miller wrote:
> > From: Michał Mirosław <mirq-linux@rere.qmqm.pl>
> > Date: Tue, 24 May 2011 11:14:37 +0200
> > 
> > > On Thu, May 19, 2011 at 12:03:31PM +0200, Michał Mirosław wrote:
> > >> On Mon, May 16, 2011 at 02:09:58PM -0400, David Miller wrote:
> > >> > You guys really need to sort this out properly.
> > >> > Please resubmit whatever final solution is agreed upon.
> > >> I noticed that v2.6.39 was tagged today. We should definitely remove
> > >> NETIF_F_COMPAT so it won't bite us in the future. The other patch that
> > >> fixes ethtool_ops->set_flags compatibility is a bugfix, so it should go
> > >> in - if we decide that the SFEATURES compatibility should be removed
> > >> it won't matter.
> > >> 
> > >> Ben, do you agree?
> > > Ping?
> > > http://patchwork.ozlabs.org/patch/95552/
> > > (this is a bugfix, so should go to stable)
> > > 
> > > http://patchwork.ozlabs.org/patch/95753/
> > > (removes ETHTOOL_F_COMPAT; this we need to decide on)
> > You and Ben are still arguing over details.
> > 
> > I want fresh versions of these patches (yes, both of them) once
> > all of the issues are resolved.
> 
> We could just wait for 2.6.40 and pretend this code part never existed. ;-)

I think I will make ethtool check for a minimum kernel version of 2.6.40
before using ETHTOOL_{G,S}FEATURES.

> I'll rebase the first patch tomorrow. Without it the compatibility in
> ETHTOOL_SFEATURES for non-converted drivers is busted wrt set_flags.

This is an improvement, but I still think the fallback is fundamentally
broken - there's no good way for userland to tell what (if anything)
went wrong when the return value has ETHTOOL_F_COMPAT set.

Ben.

-- 
Ben Hutchings, Senior Software Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.