On Sat, Jun 3, 2017 at 8:20 PM, Lee, Chun-Yi <joeyli.kernel@xxxxxxxxx> wrote:
> In hotplug logic, it always indicates non-specific failure to
> platform through _OST when handing acpi hot-remove event failed. Then
> platform terminates the hot-remove process but it can not identify
> the reason.
>
> Base on current hot-remove code, there have two situations that it
> returns busy:
> - OSPM try to offline an individual device, but the device offline
> function returns busy.
> - When the ejection event is applied to an "not offlined yet" container.
> OSPM send kobject change event to userspace and returns busy.
>
> Both of them will returns -EBUSY to acpi device hotplug function then
> hotplug function indicates non-specific failure to platform just like
> any other error, e.g. -ENODEV or -EIO.
>
> The benefit to platform for identifying the OS busy state is that
> platform can be applied different approach to handle the busy but
> not just terminate the hot-remove process by unknow reason. For
> example, platform can wait for a while then triggers hot-remove
> again.
>
> This RFC patch adds one more parameter to the handler function of
> acpi generic hotplug event to give the function a chance to propose
> the return code of _OST. In this case, it sets ost return code to
> ACPI_OST_SC_DEVICE_BUSY when the acpi hot remove function returns
> -EBUSY.
> -static int acpi_generic_hotplug_event(struct acpi_device *adev, u32 type)
> +static int acpi_generic_hotplug_event(struct acpi_device *adev, u32 type,
> + u32 *ost_code)
> {
> + int error = -EINVAL;
> +
> switch (type) {
> case ACPI_NOTIFY_BUS_CHECK:
> return acpi_scan_bus_check(adev);
> @@ -389,9 +392,11 @@ static int acpi_generic_hotplug_event(struct acpi_device *adev, u32 type)
> }
> acpi_evaluate_ost(adev->handle, ACPI_NOTIFY_EJECT_REQUEST,
> ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
> - return acpi_scan_hot_remove(adev);
> + error = acpi_scan_hot_remove(adev);
> + if (error == -EBUSY && ost_code)
> + *ost_code = ACPI_OST_SC_DEVICE_BUSY;
> }
> - return -EINVAL;
> + return error;
> }
Wit this change you spear a logic on two functions...
>
> void acpi_device_hotplug(struct acpi_device *adev, u32 src)
> @@ -413,7 +418,7 @@ void acpi_device_hotplug(struct acpi_device *adev, u32 src)
> if (adev->flags.is_dock_station) {
> error = dock_notify(adev, src);
> } else if (adev->flags.hotplug_notify) {
> - error = acpi_generic_hotplug_event(adev, src);
> + error = acpi_generic_hotplug_event(adev, src, &ost_code);
> if (error == -EPERM) {
> ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
> goto err_out;
...instead (since the first one is defined as static) I would propose
to change only here like
switch (error) {
case -EPERM:
ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
break;
case -EBUSY:
ost_code = ACPI_OST_SC_DEVICE_BUSY;
break;
}
if (error)
goto err_out;
This is less intrusive and more flexible to modifications in the
future (might be split to a helper, might be easily extended, etc).
--
With Best Regards,
Andy Shevchenko
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