linux-kernel - Re: [PATCH net-next 09/15] ethernet/dlink: use core min/max MTU checking

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Message-ID: <20161022115432.5936df44@kant>
Date:   Sat, 22 Oct 2016 11:54:32 +0200
From:   Stefan Richter <stefanr@...6.in-berlin.de>
To:     Jarod Wilson <jarod@...hat.com>
Cc:     Denis Kirjanov <kda@...ux-powerpc.org>,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH net-next 09/15] ethernet/dlink: use core min/max MTU
 checking

On Oct 18 Jarod Wilson wrote:
> On Tue, Oct 18, 2016 at 04:45:51PM +0300, Denis Kirjanov wrote:
> > On 10/17/16, Jarod Wilson <jarod@...hat.com> wrote:
[...]
> > > --- a/drivers/net/ethernet/dlink/sundance.c
> > > +++ b/drivers/net/ethernet/dlink/sundance.c
> > > @@ -580,6 +580,10 @@ static int sundance_probe1(struct pci_dev *pdev,
> > >  	dev->ethtool_ops = &ethtool_ops;
> > >  	dev->watchdog_timeo = TX_TIMEOUT;
> > >
> > > +	/* MTU range: 68 - 8191 */
> > > +	dev->min_mtu = ETH_MIN_MTU;
> > > +	dev->max_mtu = 8191;
> > > +  
> > ICPlus datasheet defines the max frame size like 0x1514 or 0x4491
> > based on the RcvLargeFrames bit in the MACCtrl0 register  
> 
> I do anticipate this patchset might bring to light some inaccuracies in
> min/max mtu values currently implemented in various drivers, but for the
> moment, I'm going for 100% identical behavior with what's currently in the
> driver, and if you'll look down below...
> 
> > >  	pci_set_drvdata(pdev, dev);
> > >
> > >  	i = register_netdev(dev);
> > > @@ -713,8 +717,6 @@ static int sundance_probe1(struct pci_dev *pdev,
> > >
> > >  static int change_mtu(struct net_device *dev, int new_mtu)
> > >  {
> > > -	if ((new_mtu < 68) || (new_mtu > 8191)) /* Set by RxDMAFrameLen */  
> 
>                                          ^^^^
> The 8191 was simply transplanted from right here. I think altering the
> value should be the subject of a separate patch.

You transplanted the value but dropped the comment.  Though Denis' reply
sounds like the comment should have been /* FIXME, set by RxDMAFrameLen */.
-- 
Stefan Richter
-======----- =-=- =-==-
http://arcgraph.de/sr/