Re: [PATCH] softirq: Provide a handshake for canceling tasklets via polling on PREEMPT_RT

From: Tejun Heo
Date: Wed Aug 13 2025 - 14:07:27 EST


Hello,

On Wed, Aug 13, 2025 at 08:33:11AM +0200, Sebastian Andrzej Siewior wrote:
...
> > The intention is to convert all BH users to workqueue-BH and remove BH
> > (that's what Linus wants and why workqueue-BH came to be), so the APIs
> > should be able to match up, I'm afraid. There were some attempts at pushing
> > the conversion but we've only made minimal progress. If you're looking at BH
> > users anyway and feel like it, please feel free to convert them.
>
> I understand this but I am talking about legacy users:
>
> | drivers/atm/eni.c: tasklet_disable_in_atomic(&ENI_DEV(vcc->dev)->task);
> | drivers/net/wireless/ath/ath9k/beacon.c: tasklet_disable_in_atomic(&sc->bcon_tasklet);
> | drivers/pci/controller/pci-hyperv.c: tasklet_disable_in_atomic(&channel->callback_event);
>
> This is what is left. (There is also i915 but this is "special").
> So we are talking about establishing an API and behaviour for those here
> after we painfully managed converting everyone else away:

Right, given how early in conversion, we can definitely leave this as
something to think about later. I have no objection to leave it be for now.

Thanks.

--
tejun