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

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Message-ID: <CAJZ5v0gcokw72q5uX-3pbBEZtJdCaWHN1vat8yPNQ3SXMgeD4g@mail.gmail.com>
Date:   Thu, 29 Jun 2023 18:18:01 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Michal Wilczynski <michal.wilczynski@...el.com>
Cc:     linux-acpi@...r.kernel.org, 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,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>
Subject: Re: [PATCH v5 09/10] acpi/nfit: Move handler installing logic to driver

On Fri, Jun 16, 2023 at 6:51 PM Michal Wilczynski
<michal.wilczynski@...el.com> 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);

It's totally not necessary to rename the ACPI device variable here.

Just add

struct acpi_device *adev = data;

to this function.

> +       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);
>  }
>
>  static void acpi_nfit_update_notify(struct device *dev, acpi_handle handle)
> @@ -3465,7 +3478,6 @@ static struct acpi_driver acpi_nfit_driver = {
>         .ops = {
>                 .add = acpi_nfit_add,
>                 .remove = acpi_nfit_remove,
> -               .notify = acpi_nfit_notify,
>         },
>  };
>
> --