Re: [PATCH 3/5] ASoC: SDCA: Fix cleanup inversion in class driver

[Charles Keepax <ckeepax@opensource.cirrus.com>]

On Wed, Apr 08, 2026 at 02:43:59PM +0100, Mark Brown wrote:
> On Wed, Apr 08, 2026 at 10:38:33AM +0100, Charles Keepax wrote:
> 
> > This led to a cleanup inversion where the devm cleanup for the parent
> > Soundwire IRQ runs before the handler that removes the function drivers.
> > So the parent IRQ is destroyed before the function drivers had a chance
> > to do any cleanup and remove their IRQ handlers.
> 
> > Move the registrations of the function driver cleanup into
> > class_boot_work() after the function drivers are registered, so that it
> > runs before the cleanup of the parent SoundWire IRQ handler.
> 
> > +static void class_remove_functions(void *data)
> > +{
> > +	struct sdca_class_drv *drv = data;
> > +
> > +	cancel_work_sync(&drv->boot_work);
> > +
> > +	sdca_dev_unregister_functions(drv->sdw);
> > +}
> 
> > @@ -157,6 +166,11 @@ static void class_boot_work(struct work_struct *work)
> >  	if (ret)
> >  		goto err;
> >  
> > +	/* Ensure function drivers are removed before the IRQ is destroyed */
> > +	ret = devm_add_action_or_reset(drv->dev, class_remove_functions, drv);
> > +	if (ret)
> > +		goto err;
> > +
> 
> This means we register the cleanup of boot_work from boot_work which
> seems a bit fun and...
> 
> > -static void class_dev_remove(void *data)
> > -{
> > -	struct sdca_class_drv *drv = data;
> > -
> > -	cancel_work_sync(&drv->boot_work);
> 
> ...what now cancels boot_work if we somehow manage to remove before
> boot_work has completed (possibly even before it's scheduled)?

Hm... yeah I think you are right there is still an issue here.

I think the boot work sync should stay in the original remove
callback. The sequence of concern was:

1) driver probes
2) boot work runs
3) boot work is scheduled
4) driver removed
5) boot work completes

I think this current patch addresses calling
sdca_dev_unregister_functions() but we don't really want any of
boot work running once the driver starts being removed.

I will respin a v2.

Thanks,
Charles