net: stmmac: Do not accept invalid MTU values

The maximum MTU value is determined by the maximum size of TX FIFO so
that a full packet can fit in the FIFO. Add a check for this in the MTU
change callback.

Also check if provided and rounded MTU does not passes the maximum limit
of 16K.

Changes from v2:
- Align MTU before checking if its valid

Fixes: 7ac6653a08 ("stmmac: Move the STMicroelectronics driver")
Signed-off-by: Jose Abreu <Jose.Abreu@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jose Abreu 2019-12-18 11:17:37 +01:00 committed by David S. Miller
parent 5d626c879e
commit eaf4fac478

View File

@ -3827,12 +3827,24 @@ static void stmmac_set_rx_mode(struct net_device *dev)
static int stmmac_change_mtu(struct net_device *dev, int new_mtu)
{
struct stmmac_priv *priv = netdev_priv(dev);
int txfifosz = priv->plat->tx_fifo_size;
if (txfifosz == 0)
txfifosz = priv->dma_cap.tx_fifo_size;
txfifosz /= priv->plat->tx_queues_to_use;
if (netif_running(dev)) {
netdev_err(priv->dev, "must be stopped to change its MTU\n");
return -EBUSY;
}
new_mtu = STMMAC_ALIGN(new_mtu);
/* If condition true, FIFO is too small or MTU too large */
if ((txfifosz < new_mtu) || (new_mtu > BUF_SIZE_16KiB))
return -EINVAL;
dev->mtu = new_mtu;
netdev_update_features(dev);