Re: [PATCH v7 2/4] workqueue: Separate sysfs mutable vs immutable wq attribute sanitizing

[Tvrtko Ursulin]

On 23/10/2026 22:28, Tejun Heo wrote:
> Hello, Tvrtko.
>
> On Thu, Oct 22, 2026 at 10:38:46AM +0100, Tvrtko Ursulin wrote:
> > +/* Sanitize attributes not modifiable via sysfs. */
> > +static void
> > +sanitize_immutable_workqueue_attrs(struct workqueue_struct *wq,
> > +				   struct workqueue_attrs *attrs)
> > ...
> > +/* Sanitize attributes modifiable via sysfs. */
> > +static void
> > +sanitize_mutable_workqueue_attrs(struct workqueue_struct *wq,
> > +				 struct workqueue_attrs *attrs)
> > ...
> > +static void
> > +sanitize_workqueue_attrs(struct workqueue_struct *wq,
> > +				 struct workqueue_attrs *attrs)
> > +{
> > +	sanitize_immutable_workqueue_attrs(wq, attrs);
> > +	sanitize_mutable_workqueue_attrs(wq, attrs);
> > +}
>
> The three helpers seem a bit excessive for what they do, and the
> immutable call in sanitize_workqueue_attrs() is redundant, as
> apply_wqattrs_prepare() runs sanitize_immutable_workqueue_attrs() on
> both of its copies anyway.

Okay I dropped sanitize_workqueue_attrs() locally. I was trying to 
express the logic behind mutable and immutable, which also leads me to...

> Could the comment on sanitize_immutable_workqueue_attrs() state the
> contract? These attrs follow from the workqueue flags and are enforced
> on every apply, apply_workqueue_attrs() callers included, not only
> sysfs.

...the topic of what would be the best commentary for both.

Would these comments work:

/*
 * Sanitize attributes derived from the workqueue flags and which need 
to be
 * enforced on every attribute application.
 */
static void
sanitize_immutable_workqueue_attrs(struct workqueue_struct *wq,
				   struct workqueue_attrs *attrs)
{
	if (wq->flags & __WQ_ORDERED)
		attrs->ordered = true;
}

/*
 * Sanitize attributes derived from the workqueue flags and which need 
to be
 * enforced only on workqueue creation.
 */
static void
sanitize_mutable_workqueue_attrs(struct workqueue_struct *wq,
				 struct workqueue_attrs *attrs)
{
	if (wq->flags & WQ_HIGHPRI)
		attrs->nice = HIGHPRI_NICE_LEVEL;
}

Regards,

Tvrtko