Re: [PATCH v2 1/6] device property: Helper to match multiple connections

Andy Shevchenko
2022-02-20T11:17:49Z

On Fri, Feb 18, 2022 at 11:00:45AM -0800, Bjorn Andersson wrote:
> On Wed 09 Feb 04:30 PST 2022, Andy Shevchenko wrote:
> > On Mon, Feb 07, 2022 at 07:19:39PM -0800, Bjorn Andersson wrote:

...

> > > +int fwnode_connection_find_matches(struct fwnode_handle *fwnode,
> > > + const char *con_id, void *data,
> > > + devcon_match_fn_t match,
> > > + void **matches, unsigned int matches_len)
> > > +{
> > > + unsigned int count;
> > > +
> > > + if (!fwnode || !match || !matches)
> >
> > !matches case may be still useful to get the count and allocate memory by
> > caller. Please, consider this case.
> >
>
> As discussed in previous version, and described in the commit message,
> the returned value of "match" is a opaque pointer to something which
> has to be passed back to the caller in order to be cleaned up.
>
> E.g. the typec mux code returns a pointer to a typec_mux/switch object
> with a refcounted struct device within, or an ERR_PTR().
>
> So unfortunately we can must gather the results into matches and pass it
> back to the caller to take consume or clean up.

It's fine. You have **matches, means pointer of an opaque pointer.
What I'm talking about is memory allocation for and array of _pointers_.
That's what caller very much aware of and can allocate on heap. So, please
consider this case.

--
With Best Regards,
Andy Shevchenko