Re: [PATCH 5/6] perf/core: Use ioctl to communicate driver configuration to kernel

[Mathieu Poirier]

On Tue, 3 Jul 2018 at 07:40, Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> On Mon, Jul 02, 2018 at 04:33:29PM -0600, Mathieu Poirier wrote:
>
> SNIP
>
> > +static int
> > +perf_event_process_drv_config(struct perf_event *event, char *config_str)
> > +{
> > +     int ret = -EINVAL;
> > +     void *drv_data;
> > +
> > +     /* Make sure ctx.mutex it held */
> > +     lockdep_assert_held(&event->ctx->mutex);
> > +
> > +     /* Children take their configuration from their parent */
> > +     if (WARN_ON_ONCE(event->parent))
> > +             goto out;
> > +
> > +     drv_data = event->pmu->drv_config_validate(event, config_str);
> > +     if (!drv_data)
> > +             goto out;
>
> what's this check for? doc does not mention that,
> also the coresight callback does not return NULL
>

Very true - thanks for pointing this out.

Mathieu

> jirka