[PATCH net-next v1 4/4] net: lan966x: generate software timestamp just before the doorbell

[Vladimir Oltean]

On Thu, May 08, 2025 at 08:22:39PM +0800, Jason Xing wrote:
> Thanks for the kind reply.
> 
> It looks like how to detect depends on how the bpf prog is written?
> Mostly depends on how the writer handles this data part. Even though
> we don't guarantee on how to ask users/admins to write/adjust their
> bpf codes, it's not that convenient for them if this patch is applied,
> to be frank. I'm not pushing you to accept this patch, just curious on
> "how and why". Now I can guess why you're opposed to it....

The BPF program is not user-generated, it is run in the context of the
function you're moving.

skb_tx_timestamp()
-> skb_clone_tx_timestamp()
   -> classify()
      -> ptp_classify_raw()
         -> bpf_prog_run(ptp_insns, skb)