linux-kernel - Re: [PATCH v5 09/10] acpi/nfit: Move handler installing logic to driver

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Message-ID: <81dbbc8f-fc05-754d-56bf-5e74169b8dc8@intel.com>
Date:   Fri, 30 Jun 2023 18:56:43 +0200
From:   "Wilczynski, Michal" <michal.wilczynski@...el.com>
To:     Dan Williams <dan.j.williams@...el.com>,
        <linux-acpi@...r.kernel.org>
CC:     <rafael@...nel.org>, <vishal.l.verma@...el.com>, <lenb@...nel.org>,
        <dave.jiang@...el.com>, <ira.weiny@...el.com>,
        <rui.zhang@...el.com>, <linux-kernel@...r.kernel.org>,
        <nvdimm@...ts.linux.dev>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>
Subject: Re: [PATCH v5 09/10] acpi/nfit: Move handler installing logic to
 driver



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@...el.com>
>> Signed-off-by: Michal Wilczynski <michal.wilczynski@...el.com>
>> ---
>>  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.

>
> An additional cleanup opportunity with the ->add() path fully devm
> instrumented would be to just delete acpi_nfit_remove() since it is
> optional and serves no purpose.

Will do,

Thanks !