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

Jason Xing kerneljasonxing at gmail.com
Thu May 8 07:16:19 PDT 2025


On Thu, May 8, 2025 at 8:40 PM Vladimir Oltean <olteanv at gmail.com> wrote:
>
> 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)

Right, I'll drop this patch from the series then.

Thanks,
Jason



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