Re: [PATCH v3 2/8] ACPI: property: Tie data nodes to acpi handles

["Rafael J. Wysocki" <rafael@kernel.org>]

On Fri, May 27, 2022 at 11:02 AM Sakari Ailus
<sakari.ailus@linux.intel.com> wrote:
>
> Hi Rafael,
>
> On Thu, May 26, 2022 at 09:19:17PM +0200, Rafael J. Wysocki wrote:
> > > +static int acpi_tie_nondev_subnodes(struct acpi_device_data *data)
> > > +{
> > > +       struct acpi_data_node *dn;
> > > +
> > > +       list_for_each_entry(dn, &data->subnodes, sibling) {
> > > +               acpi_status status;
> > > +               int ret;
> > > +
> > > +               status = acpi_attach_data(dn->handle, acpi_nondev_subnode_tag, dn);
> > > +               if (ACPI_FAILURE(status)) {
> > > +                       acpi_handle_err(dn->handle, "Can't tag data node\n");
> > > +                       return 0;
> > > +               }
> > > +
> > > +               ret = acpi_tie_nondev_subnodes(&dn->data);
> > > +               if (ret)
> > > +                       return ret;
> >
> > Is it actually possible that this returns anything different from 0?
>
> acpi_attach_data() involves allocating memory and resolving a reference.
> Both can fail.

Yes, they can, but the value returned by acpi_attach_data() is
effectively ignored above (except for printing the error message,
which BTW could be "info" and provide more information).

I don't see how acpi_tie_nondev_subnodes() can produce a nonzero return value.