Re: [PATCH v1 14/16] soundwire: Use acpi_dev_for_each_child()

Rafael J. Wysocki
2022-06-09T16:13:29Z

On Thu, Jun 9, 2022 at 5:23 PM Pierre-Louis Bossart
<pierre-louis.bossart@linux.intel.com> wrote:
>
> Thanks Rafael. This looks mostly good but I have a doubt on the error
> handling, see below.
>
> > +static int sdw_acpi_check_duplicate(struct acpi_device *adev, void *data)
> > +{
> > + struct sdw_acpi_child_walk_data *cwd = data;
> > + struct sdw_bus *bus = cwd->bus;
> > + struct sdw_slave_id id;
> > +
> > + if (adev == cwd->adev)
> > + return 0;
> > +
> > + if (!find_slave(bus, adev, &id))
> > + return 0;
> > +
> > + if (cwd->id.sdw_version != id.sdw_version || cwd->id.mfg_id != id.mfg_id ||
> > + cwd->id.part_id != id.part_id || cwd->id.class_id != id.class_id)
> > + return 0;
> > +
> > + if (cwd->id.unique_id != id.unique_id) {
> > + dev_dbg(bus->dev,
> > + "Valid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
> > + cwd->id.unique_id, id.unique_id, cwd->id.mfg_id,
> > + cwd->id.part_id);
> > + cwd->ignore_unique_id = false;
> > + return 0;
> > + }
> > +
> > + dev_err(bus->dev,
> > + "Invalid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
> > + cwd->id.unique_id, id.unique_id, cwd->id.mfg_id, cwd->id.part_id);
> > + return -ENODEV;
>
> if this error happens, I would guess it's reported ....
>
> > +}
> > +
> > +static int sdw_acpi_find_one(struct acpi_device *adev, void *data)
> > +{
> > + struct sdw_bus *bus = data;
> > + struct sdw_acpi_child_walk_data cwd = {
> > + .bus = bus,
> > + .adev = adev,
> > + .ignore_unique_id = true,
> > + };
> > + int ret;
> > +
> > + if (!find_slave(bus, adev, &cwd.id))
> > + return 0;
> > +
> > + /* Brute-force O(N^2) search for duplicates. */
> > + ret = acpi_dev_for_each_child(ACPI_COMPANION(bus->dev),
> > + sdw_acpi_check_duplicate, &cwd);
> > + if (ret)
> > + return ret;
>
> ... here, but I don't see this being propagated further...
>
> > +
> > + if (cwd.ignore_unique_id)
> > + cwd.id.unique_id = SDW_IGNORED_UNIQUE_ID;
> > +
> > + /* Ignore errors and continue. */
> > + sdw_slave_add(bus, &cwd.id, acpi_fwnode_handle(adev));
> > + return 0;
> > +}
> > +
> > /*
> > * sdw_acpi_find_slaves() - Find Slave devices in Master ACPI node
> > * @bus: SDW bus instance
> > @@ -135,8 +200,7 @@ static bool find_slave(struct sdw_bus *b
> > */
> > int sdw_acpi_find_slaves(struct sdw_bus *bus)
> > {
> > - struct acpi_device *adev, *parent;
> > - struct acpi_device *adev2, *parent2;
> > + struct acpi_device *parent;
> >
> > parent = ACPI_COMPANION(bus->dev);
> > if (!parent) {
> > @@ -144,52 +208,7 @@ int sdw_acpi_find_slaves(struct sdw_bus
> > return -ENODEV;
> > }
> >
> > - list_for_each_entry(adev, &parent->children, node) {
> > - struct sdw_slave_id id;
> > - struct sdw_slave_id id2;
> > - bool ignore_unique_id = true;
> > -
> > - if (!find_slave(bus, adev, &id))
> > - continue;
> > -
> > - /* brute-force O(N^2) search for duplicates */
> > - parent2 = parent;
> > - list_for_each_entry(adev2, &parent2->children, node) {
> > -
> > - if (adev == adev2)
> > - continue;
> > -
> > - if (!find_slave(bus, adev2, &id2))
> > - continue;
> > -
> > - if (id.sdw_version != id2.sdw_version ||
> > - id.mfg_id != id2.mfg_id ||
> > - id.part_id != id2.part_id ||
> > - id.class_id != id2.class_id)
> > - continue;
> > -
> > - if (id.unique_id != id2.unique_id) {
> > - dev_dbg(bus->dev,
> > - "Valid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
> > - id.unique_id, id2.unique_id, id.mfg_id, id.part_id);
> > - ignore_unique_id = false;
> > - } else {
> > - dev_err(bus->dev,
> > - "Invalid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
> > - id.unique_id, id2.unique_id, id.mfg_id, id.part_id);
> > - return -ENODEV;
> > - }
> > - }
> > -
> > - if (ignore_unique_id)
> > - id.unique_id = SDW_IGNORED_UNIQUE_ID;
> > -
> > - /*
> > - * don't error check for sdw_slave_add as we want to continue
> > - * adding Slaves
> > - */
> > - sdw_slave_add(bus, &id, acpi_fwnode_handle(adev));
> > - }
> > + acpi_dev_for_each_child(parent, sdw_acpi_find_one, bus);
>
> ... here?
>
> It looks like a change in the error handling flow where
> sdw_acpi_find_slaves() is now returning 0 (success) always?
>
> Shouldn't the return of sdw_acpi_find_one() be trapped, e.g. with
>
> return acpi_dev_for_each_child(parent, sdw_acpi_find_one, bus);

Sure, I'll do that. Thanks!