Re: [net-next 1/3] net: dsa: optimize tx timestamp request handling

[Richard Cochran]

On Fri, Apr 16, 2021 at 08:36:53PM +0800, Yangbo Lu wrote:
> Optimization could be done on dsa_skb_tx_timestamp(), and dsa device
> drivers should adapt to it.
> 
> - Check SKBTX_HW_TSTAMP request flag at the very beginning, instead of in
>   port_txtstamp, so that most skbs not requiring tx timestamp just return.
> 
> - No longer to identify PTP packets, and limit tx timestamping only for PTP
>   packets. If device driver likes, let device driver do.
> 
> - It is a waste to clone skb directly in dsa_skb_tx_timestamp().
>   For one-step timestamping, a clone is not needed. For any failure of
>   port_txtstamp (this may usually happen), the skb clone has to be freed.
>   So put skb cloning into port_txtstamp where it really needs.

This patch changes three things ^^^ at once.  These are AFAICT
independent changes, and so please break this one patch into three for
easier review.

Thanks,
Richard