Re: [PATCH 001/001] forcedeth: Don't enable hardware vlan support on hardware that doesn't support it

[Stephen Hemminger <shemminger@vyatta.com>]

On Wed, 15 Jun 2011 17:08:18 -0400
Antoine Reversat <a.reversat@gmail.com> wrote:

> On Wed, Jun 15, 2011 at 4:53 PM, Stephen Hemminger
> <stephen.hemminger@vyatta.com> wrote:
> >
> > This shouldn't be necessary. rx_register should not be called
> > unless NETIF_F_HW_VLAN_RX is set; and device should not be setting
> > NETIF_F_HW_VLAN_RX unless DEV_HAS_VLAN is set.
> 
> I can confirm that rx_register gets called on hardware that doesn't
> have vlan support (namely MCP79).
> 
> From what I can see in vlan.c (in register_vlan_dev) there is no check
> on the features of the device before calling the register function :
> 
>     if (ngrp) {
>         if (ops->ndo_vlan_rx_register)
>             ops->ndo_vlan_rx_register(real_dev, ngrp);
>         rcu_assign_pointer(real_dev->vlgrp, ngrp);
>     }
> 
> If the function exists, it's called. Should I send a patch to call the
> function only if the hardware supports it ?
> 
> >
> > The real problem is vlan_dev.c, and applies to all devices.

That is was suggesting because other drivers may have the same issue
where they need to define rx_register for some hardware and control
usage of vlan by the feature bits.