On Sun, Jan 15, 2017 at 12:55:02AM +0200, Rami Rosen wrote:
> Hi, Florian,
>
> > +}
> > +
> > +static int aq_ndev_change_mtu(struct net_device *ndev, int new_mtu)
> > +{
> > + struct aq_nic_s *aq_nic = (struct aq_nic_s *)netdev_priv(ndev);
> > + int err = 0;
> > +
> > + if (new_mtu == ndev->mtu) {
> > + err = 0;
> > + goto err_exit;
> > + }
> > + if (new_mtu < 68) {
> > + err = -EINVAL;
> > + goto err_exit;
> > + }
Actually, the core will already impose min/max of ETH_MIN_MTU and
ETH_DATA_LEN. See
commit a52ad514fdf3b8a57ca4322c92d2d8d5c6182485
Author: Jarod Wilson <ja...@redhat.com>
Date: Fri Oct 7 22:04:34 2016 -0400
net: deprecate eth_change_mtu, remove usage
With centralized MTU checking, there's nothing productive done by
eth_change_mtu that isn't already done in dev_set_mtu, so mark it as
deprecated and remove all usage of it in the kernel. All callers have been
audited for calls to alloc_etherdev* or ether_setup directly, which means
they all have a valid dev->min_mtu and dev->max_mtu. Now eth_change_mtu
prints out a netdev_warn about being deprecated, for the benefit of
out-of-tree drivers that might be utilizing it.
Of note, dvb_net.c actually had dev->mtu = 4096, while using
eth_change_mtu, meaning that if you ever tried changing it's mtu, you
couldn't set it above 1500 anymore. It's now getting dev->max_mtu also set
to 4096 to remedy that.
Andrew
