[v2] net: stmmac: fix maxmtu assignment to be within valid range

From: "Kweh, Hock Leong" <hock.leong.kweh@intel.com>

There is no checking valid value of maxmtu when getting it from device tree.
This resolution added the checking condition to ensure the assignment is
made within a valid range.

Signed-off-by: Kweh, Hock Leong <hock.leong.kweh@intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

> -----Original Message-----
> From: Kweh, Hock Leong
> Sent: Friday, January 06, 2017 6:08 PM
> To: David S. Miller <davem@davemloft.net>; Joao Pinto
> <Joao.Pinto@synopsys.com>; Giuseppe CAVALLARO <peppe.cavallaro@st.com>;
> seraphin.bonnaffe@st.com; Jarod Wilson <jarod@redhat.com>; Andy
> Shevchenko <andy.shevchenko@gmail.com>
> Cc: Alexandre TORGUE <alexandre.torgue@gmail.com>; Joachim Eastwood
> <manabian@gmail.com>; Niklas Cassel <niklas.cassel@axis.com>; Johan Hovold
> <johan@kernel.org>; pavel@ucw.cz; Kweh, Hock Leong
> <hock.leong.kweh@intel.com>; lars.persson@axis.com; netdev
> <netdev@vger.kernel.org>; LKML <linux-kernel@vger.kernel.org>
> Subject: [PATCH v2] net: stmmac: fix maxmtu assignment to be within valid
> range
> 
> From: "Kweh, Hock Leong" <hock.leong.kweh@intel.com>
> 
> There is no checking valid value of maxmtu when getting it from device tree.
> This resolution added the checking condition to ensure the assignment is made
> within a valid range.
> 
> Signed-off-by: Kweh, Hock Leong <hock.leong.kweh@intel.com>

I am going to submit V3.

> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |    8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 92ac006..4df555e 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -3345,8 +3345,14 @@ 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;
> +	else if (priv->plat->maxmtu != 0)
> +		netdev_warn(priv->dev,
> +			    "%s: warning: maxmtu having invalid value (%d)\n",
> +			    __func__, priv->plat->maxmtu);
> 
>  	if (flow_ctrl)
>  		priv->flow_ctrl = FLOW_AUTO;	/* RX/TX pause on */
> --
> 1.7.9.5