On Fri, Aug 30, 2019 at 4:34 PM Andy Shevchenko
<andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
>
> When the commit 68bdb6773289
>
> ("ACPI: add support for ACPI reconfiguration notifiers")
>
> introduced reconfiguration notifiers it misses the point that the ACPI table,
> which may be loaded and then unloaded via ConfigFS, can contain devices that are
> not enumerated by their parents.
>
> In such case the stale platform device is dangling in the system while the rest
> of the devices from the same table are already gone.
>
> Introduce acpi_platform_device_remove_notify() notifier that, in similar way to
> I²C or SPI buses, unregisters the platform devices on table removal event.
>
> Depends-on: 00500147cbd3 ("drivers: Introduce device lookup variants by ACPI_COMPANION device")
> Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> ---
> drivers/acpi/acpi_platform.c | 43 ++++++++++++++++++++++++++++++++++++
> drivers/acpi/scan.c | 1 +
> 2 files changed, 44 insertions(+)
>
> diff --git a/drivers/acpi/acpi_platform.c b/drivers/acpi/acpi_platform.c
> index 00ec4f2bf015..dfcd6210828e 100644
> --- a/drivers/acpi/acpi_platform.c
> +++ b/drivers/acpi/acpi_platform.c
> @@ -31,6 +31,44 @@ static const struct acpi_device_id forbidden_id_list[] = {
> {"", 0},
> };
>
> +static struct platform_device *acpi_platform_device_find_by_adev(struct acpi_device *adev)
> +{
> + struct device *dev;
> +
> + dev = bus_find_device_by_acpi_dev(&platform_bus_type, adev);
> + return dev ? to_platform_device(dev) : NULL;
> +}
> +
> +static int acpi_platform_device_remove_notify(struct notifier_block *nb,
> + unsigned long value, void *arg)
> +{
> + struct acpi_device *adev = arg;
> + struct platform_device *pdev;
> +
> + switch (value) {
> + case ACPI_RECONFIG_DEVICE_ADD:
> + /* Nothing to do here */
> + break;
> + case ACPI_RECONFIG_DEVICE_REMOVE:
> + if (!acpi_device_enumerated(adev))
> + break;
> +
> + pdev = acpi_platform_device_find_by_adev(adev);
> + if (!pdev)
> + break;
> +
> + platform_device_unregister(pdev);
> + put_device(&pdev->dev);
> + break;
> + }
> +
> + return NOTIFY_OK;
> +}
> +
> +static struct notifier_block acpi_platform_notifier = {
> + .notifier_call = acpi_platform_device_remove_notify,
> +};
> +
> static void acpi_platform_fill_resource(struct acpi_device *adev,
> const struct resource *src, struct resource *dest)
> {
> @@ -130,3 +168,8 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *adev,
> return pdev;
> }
> EXPORT_SYMBOL_GPL(acpi_create_platform_device);
> +
> +void __init acpi_platform_init(void)
> +{
> + acpi_reconfig_notifier_register(&acpi_platform_notifier);
> +}
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index aad6be5c0af0..915650bf519f 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -2174,6 +2174,7 @@ int __init acpi_scan_init(void)
> acpi_pci_root_init();
> acpi_pci_link_init();
> acpi_processor_init();
> + acpi_platform_init();
> acpi_lpss_init();
> acpi_apd_init();
> acpi_cmos_rtc_init();
> --
Applying (with minor modifications) as 5.5 material, thanks!
