On Thu, Jun 09, 2022 at 03:44:27PM +0200, 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). Hmm... Does it true for DT overlays? Not an expert in DT overlays, though, adding Rob and Frank. > 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. I'm going to look the individual patches. -- With Best Regards, Andy Shevchenko
