On Fri Dec 09 2022, Vladimir Oltean wrote:
> ptp_classify_raw() is not exactly cheap, since it invokes a BPF program
> for every skb in the receive path.

Only if CONFIG_NET_PTP_CLASSIFY is set.

> For switches which do not provide ds->ops->port_rxtstamp(), running
> ptp_classify_raw() provides precisely nothing, so check for the
> presence of the function pointer first, since that is much cheaper.
>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>