linux-kernel - Re: [PATCH net-next 00/15] ethernet: use core min/max MTU checking

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Message-ID: <20161017202943.GP14983@redhat.com>
Date:   Mon, 17 Oct 2016 16:29:43 -0400
From:   Jarod Wilson <jarod@...hat.com>
To:     David Miller <davem@...emloft.net>
Cc:     linux-kernel@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH net-next 00/15] ethernet: use core min/max MTU checking

On Mon, Oct 17, 2016 at 04:03:41PM -0400, David Miller wrote:
> From: Jarod Wilson <jarod@...hat.com>
> Date: Mon, 17 Oct 2016 15:54:02 -0400
> 
> > For the most part, every patch does the same essential thing: removes the
> > MTU range checking from the drivers' ndo_change_mtu function, puts those
> > ranges into the core net_device min_mtu and max_mtu fields, and where
> > possible, removes ndo_change_mtu functions entirely.
> 
> Jarod, please read my other posting.

Done, didn't see it until just after I'd hit send, have replied there as
well.

> You've positively broken the maximum MTU for all of these drivers.
> 
> That's not cool.
>
> And this series fixing things doesn't make things better, because now
> we've significanyly broken bisection for anyone running into this
> regression.

Agreed, and my suggestion right now is to revert the 2nd patch from the
prior series. I believe it can be resubmitted after all other callers of
ether_setup() have been converted to have their own min/max_mtu.

> You should have arranged this in such a way that the drivers needing
> > 1500 byte MTU were not impacted at all by your changes, but that
> isn't what happened.

Yeah, I must admit to not looking closely enough at the state the first
two patches left things in. It was absolutely my intention to not alter
behaviour in any way, but I neglected to test sufficiently without this
additional set applied.

-- 
Jarod Wilson
jarod@...hat.com