Re: [PATCH net v2 0/3] Add missing xdp_do_flush() invocations.

Sebastian Andrzej Siewior
2023-09-20T07:54:23Z

On 2023-09-20 09:04:27 [+0200], Jesper Dangaard Brouer wrote:
> Hi Sebastian,

Hi Jesper,

> On 18/09/2023 17.36, Sebastian Andrzej Siewior wrote:
> > Hi,
> >
> > I've been looking at the drivers/ XDP users and noticed that some
> > XDP_REDIRECT user don't invoke xdp_do_flush() at the end.
>
> I'm wondering if we could detect (and WARN) in the net core e.g.
> net_rx_action() that a driver is missing a flush?
>
> The idea could be to check the per CPU (struct) bpf_redirect_info.
> Or check (per CPU) dev_flush_list.
>
> If some is worried about performance implications, then we can hide this
> under CONFIG_DEBUG_NET.

I had a WARN_ON in mind since the list has to be empty after the
completion of a NAPI callback. Now that you are bringing it up let me
actually do something…

> --Jesper

Sebastian