Re: [PATCH net] net/ncsi: Don't assume last available channel exists

[David Miller]

From: Samuel Mendoza-Jonas <sam@xxxxxxxxxxxxxxxx>
Date: Fri, 22 Sep 2017 11:00:00 +1000

> If we haven't configured a channel yet (or are in the process of doing
> so) we won't have a hot_channel - does it make more sense to
> - check against the hot_channel as currently done,
> - only check the filter size at configure time for /each/ channel,
> - only conditionally enable the .ndo_vlan_rx_add_vid net_device callback
> once we've configured a channel (eg. for ftgmac100 in the
> ftgmac100_ncsi_handler() callback?)

The last isn't so feasible.

The device shouldn't be marked attached until a channel is available,
because it seems like communication cannot occur until one is.  Right?

You could experiment with netif_device_detach()/netif_device_attach().

When the device is in the detached state, callbacks such as
->ndo_vlan_rx_add_vid() will not be invoked.