RE: [PATCH] net: stmmac: fix maxmtu assignment to be within valid range

[Kweh, Hock Leong]

> -----Original Message-----
> From: Andy Shevchenko [mailto:andy.shevchenko@xxxxxxxxx]
> Sent: Friday, January 06, 2017 5:07 AM
> To: Kweh, Hock Leong <hock.leong.kweh@xxxxxxxxx>
> Cc: David S. Miller <davem@xxxxxxxxxxxxx>; Joao Pinto
> <Joao.Pinto@xxxxxxxxxxxx>; Giuseppe CAVALLARO <peppe.cavallaro@xxxxxx>;
> seraphin.bonnaffe@xxxxxx; Jarod Wilson <jarod@xxxxxxxxxx>; Alexandre
> TORGUE <alexandre.torgue@xxxxxxxxx>; Joachim Eastwood
> <manabian@xxxxxxxxx>; Niklas Cassel <niklas.cassel@xxxxxxxx>; Johan Hovold
> <johan@xxxxxxxxxx>; Pavel Machek <pavel@xxxxxx>; lars.persson@xxxxxxxx;
> netdev <netdev@xxxxxxxxxxxxxxx>; LKML <linux-kernel@xxxxxxxxxxxxxxx>
> Subject: Re: [PATCH] net: stmmac: fix maxmtu assignment to be within valid
> range
> 
> On Thu, Jan 5, 2017 at 12:47 PM, Kweh, Hock Leong
> <hock.leong.kweh@xxxxxxxxx> wrote:
> > From: "Kweh, Hock Leong" <hock.leong.kweh@xxxxxxxxx>
> >
> > There is no checking valid value of maxmtu when getting it from devicetree.
> 
> 'Device Tree' or 'device tree' ?

Noted & Thanks. Submitting V2.

> 
> > This resolution added the checking condition to ensure the assignment
> > is made within a valid range.
> 
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > index 39eb7a6..683d59f 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > @@ -3319,7 +3319,8 @@ int stmmac_dvr_probe(struct device *device,
> >                 ndev->max_mtu = JUMBO_LEN;
> >         else
> >                 ndev->max_mtu = SKB_MAX_HEAD(NET_SKB_PAD + NET_IP_ALIGN);
> > -       if (priv->plat->maxmtu < ndev->max_mtu)
> > +       if ((priv->plat->maxmtu < ndev->max_mtu) &&
> > +           (priv->plat->maxmtu >= ndev->min_mtu))
> >                 ndev->max_mtu = priv->plat->maxmtu;
> 
> Perhaps add a warning message on else branch?

Noted & Thanks. Submitting V2.

> 
> --
> With Best Regards,
> Andy Shevchenko