Re: [PATCH v4 01/11] ASoC: SOF: core: add 'no_wq' probe and remove callbacks

[Kai Vehmanen]

Hi,

On Wed, 30 Aug 2023, Pierre-Louis Bossart wrote:

> >  	/* probe/remove/shutdown */
> > +	int (*probe_no_wq)(struct snd_sof_dev *sof_dev); /* optional */
> > +	int (*remove_no_wq)(struct snd_sof_dev *sof_dev); /* optional */
> 
> My initial PR didn't have this remove_no_wq() callback.
> 
> For symmetry it could be useful if it is meant to undo what the
> probe_no_wq() did, but conceptually the first thing we do in the remove
> is make sure that workqueue is either not scheduled or we wait until it
> completes.

I think that's exactly what the patch ends up with, remove_no_wq releases 
resources acquired in probe_no_wq, i.e. they are symmetrical.
 
> int snd_sof_device_remove(struct device *dev)
> {
> 	struct snd_sof_dev *sdev = dev_get_drvdata(dev);
> 	struct snd_sof_pdata *pdata = sdev->pdata;
> 	int ret;
> 
> 	if (IS_ENABLED(CONFIG_SND_SOC_SOF_PROBE_WORK_QUEUE))
> 		cancel_work_sync(&sdev->probe_work);

So this seems ok as well:
 - if wq is used, at remove, we first wait wq to be finished 
   and only then proceed with removal
 - the remove_no_wq is run only when the first step is completed

Br, Kai