On 6/30/2023 7:19 PM, Dan Williams wrote:
> Wilczynski, Michal wrote:
>>
>> On 6/29/2023 10:54 PM, Dan Williams wrote:
>>> Michal Wilczynski wrote:
>>>> Currently logic for installing notifications from ACPI devices is
>>>> implemented using notify callback in struct acpi_driver. Preparations
>>>> are being made to replace acpi_driver with more generic struct
>>>> platform_driver, which doesn't contain notify callback. Furthermore
>>>> as of now handlers are being called indirectly through
>>>> acpi_notify_device(), which decreases performance.
>>>>
>>>> Call acpi_dev_install_notify_handler() at the end of .add() callback.
>>>> Call acpi_dev_remove_notify_handler() at the beginning of .remove()
>>>> callback. Change arguments passed to the notify function to match with
>>>> what's required by acpi_install_notify_handler(). Remove .notify
>>>> callback initialization in acpi_driver.
>>>>
>>>> Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>>>> Signed-off-by: Michal Wilczynski <michal.wilczynski@xxxxxxxxx>
>>>> ---
>>>> drivers/acpi/nfit/core.c | 24 ++++++++++++++++++------
>>>> 1 file changed, 18 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
>>>> index 95930e9d776c..a281bdfee8a0 100644
>>>> --- a/drivers/acpi/nfit/core.c
>>>> +++ b/drivers/acpi/nfit/core.c
>>>> @@ -3312,11 +3312,13 @@ void acpi_nfit_shutdown(void *data)
>>>> }
>>>> EXPORT_SYMBOL_GPL(acpi_nfit_shutdown);
>>>>
>>>> -static void acpi_nfit_notify(struct acpi_device *adev, u32 event)
>>>> +static void acpi_nfit_notify(acpi_handle handle, u32 event, void *data)
>>>> {
>>>> - device_lock(&adev->dev);
>>>> - __acpi_nfit_notify(&adev->dev, adev->handle, event);
>>>> - device_unlock(&adev->dev);
>>>> + struct acpi_device *device = data;
>>>> +
>>>> + device_lock(&device->dev);
>>>> + __acpi_nfit_notify(&device->dev, handle, event);
>>>> + device_unlock(&device->dev);
>>>> }
>>>>
>>>> static int acpi_nfit_add(struct acpi_device *adev)
>>>> @@ -3375,12 +3377,23 @@ static int acpi_nfit_add(struct acpi_device *adev)
>>>>
>>>> if (rc)
>>>> return rc;
>>>> - return devm_add_action_or_reset(dev, acpi_nfit_shutdown, acpi_desc);
>>>> +
>>>> + rc = devm_add_action_or_reset(dev, acpi_nfit_shutdown, acpi_desc);
>>>> + if (rc)
>>>> + return rc;
>>>> +
>>>> + return acpi_dev_install_notify_handler(adev,
>>>> + ACPI_DEVICE_NOTIFY,
>>>> + acpi_nfit_notify);
>>>> }
>>>>
>>>> static void acpi_nfit_remove(struct acpi_device *adev)
>>>> {
>>>> /* see acpi_nfit_unregister */
>>>> +
>>>> + acpi_dev_remove_notify_handler(adev,
>>>> + ACPI_DEVICE_NOTIFY,
>>>> + acpi_nfit_notify);
>>> Please use devm to trigger this release rather than making
>>> acpi_nfit_remove() contain any logic.
>> I think adding separate devm action to remove event handler is not
>> necessary. I'll put the removal in the beggining of acpi_nfit_shutdown() if you
>> don't object.
> How do you plan to handle an acpi_dev_install_notify_handler() failure?
> acpi_nfit_shutdown() will need to have extra logic to know that it can
> skip acpi_dev_remove_notify_handler() in some cases and not other..
> Maybe it is ok to remove a handler that was never installed, but I would
> rather not go look that up. A devm callback for
> acpi_dev_remove_notify_handler() avoids that.
Sure, I looked at the code and it seems to me that trying to remove a callback that doesn't
exist shouldn't cause any problems. But maybe it's not very elegant and we shouldn't rely
on that behavior.
Will add separate devm action for that then.
