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

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Message-ID: <649def832ce1f_11e68529491@dwillia2-xfh.jf.intel.com.notmuch>
Date:   Thu, 29 Jun 2023 13:54:27 -0700
From:   Dan Williams <dan.j.williams@...el.com>
To:     Michal Wilczynski <michal.wilczynski@...el.com>,
        <linux-acpi@...r.kernel.org>
CC:     <rafael@...nel.org>, <dan.j.williams@...el.com>,
        <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>,
        Michal Wilczynski <michal.wilczynski@...el.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>
Subject: RE: [PATCH v5 09/10] acpi/nfit: Move handler installing logic to
 driver

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.

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.