[PATCH v2 00/16] ACPI: Get rid of the list of children in struct acpi_device

Rafael J. Wysocki
2022-06-13T20:08:03Z

On Thursday, June 9, 2022 3:44:27 PM CEST Rafael J. Wysocki wrote:
> Hi All,
>
> Confusingly enough, the ACPI subsystem stores the information on the given ACPI
> device's children in two places: as the list of children in struct acpi_device
> and (as a result of device registration) in the list of children in the embedded
> struct device.
>
> These two lists agree with each other most of the time, but not always (like in
> error paths in some cases), and the list of children in struct acpi_device is
> not generally safe to use without locking. In principle, it should always be
> walked under acpi_device_lock, but in practice holding acpi_scan_lock is
> sufficient for that too. However, its users may not know whether or not
> they operate under acpi_scan_lock and at least in some cases it is not accessed
> in a safe way (note that ACPI devices may go away as a result of hot-remove,
> unlike OF nodes).
>
> For this reason, it is better to consolidate the code that needs to walk the
> children of an ACPI device which is the purpose of this patch series.
>
> Overall, it switches over all of the users of the list of children in struct
> acpi_device to using helpers based on the driver core's mechanics and finally
> drops that list, but some extra cleanups are done on the way.
>
> Please refer to the patch changelogs for details.

Here's a v2 of this series, mostly addressing review comments, but the subjects
of the Thunderbolt and USB patches have been changed too.

Thanks!