linux-kernel - Re: [PATCH v7 7/9] acpi/nfit: Move handler installing logic to driver

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Message-ID: <CAJZ5v0hxr1h3HVq-Q5QRos3J7mDVNv0rYEZ0O1x5dfxfYeuD+Q@mail.gmail.com>
Date:   Thu, 13 Jul 2023 17:21:36 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Michal Wilczynski <michal.wilczynski@...el.com>,
        dan.j.williams@...el.com
Cc:     linux-acpi@...r.kernel.org, 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 v7 7/9] acpi/nfit: Move handler installing logic to driver

On Mon, Jul 3, 2023 at 10:03 AM 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
> acpi_nfit_shutdown(). Change arguments passed to the notify function to
> match with what's required by acpi_dev_install_notify_handler(). Remove
> .notify callback initialization in acpi_driver.
>
> Introduce a new devm action acpi_nfit_remove_notify_handler.
>
> Move acpi_nfit_notify() upwards in the file, so it can be used inside
> acpi_nfit_add() and acpi_nfit_remove_notify_handler().

Dan, any objections?

> Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> Signed-off-by: Michal Wilczynski <michal.wilczynski@...el.com>
> ---
>  drivers/acpi/nfit/core.c | 41 +++++++++++++++++++++++++++++++---------
>  1 file changed, 32 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
> index 07204d482968..124e928647d3 100644
> --- a/drivers/acpi/nfit/core.c
> +++ b/drivers/acpi/nfit/core.c
> @@ -3282,6 +3282,24 @@ static void acpi_nfit_put_table(void *table)
>         acpi_put_table(table);
>  }
>
> +static void acpi_nfit_notify(acpi_handle handle, u32 event, void *data)
> +{
> +       struct acpi_device *adev = data;
> +
> +       device_lock(&adev->dev);
> +       __acpi_nfit_notify(&adev->dev, handle, event);
> +       device_unlock(&adev->dev);
> +}
> +
> +static void acpi_nfit_remove_notify_handler(void *data)
> +{
> +       struct acpi_device *adev = data;
> +
> +       acpi_dev_remove_notify_handler(adev,
> +                                      ACPI_DEVICE_NOTIFY,
> +                                      acpi_nfit_notify);
> +}
> +
>  void acpi_nfit_shutdown(void *data)
>  {
>         struct acpi_nfit_desc *acpi_desc = data;
> @@ -3368,7 +3386,20 @@ 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;
> +
> +       rc = acpi_dev_install_notify_handler(adev,
> +                                            ACPI_DEVICE_NOTIFY,
> +                                            acpi_nfit_notify);
> +       if (rc)
> +               return rc;
> +
> +       return devm_add_action_or_reset(dev,
> +                                       acpi_nfit_remove_notify_handler,
> +                                       adev);
>  }
>
>  static void acpi_nfit_remove(struct acpi_device *adev)
> @@ -3446,13 +3477,6 @@ void __acpi_nfit_notify(struct device *dev, acpi_handle handle, u32 event)
>  }
>  EXPORT_SYMBOL_GPL(__acpi_nfit_notify);
>
> -static void acpi_nfit_notify(struct acpi_device *adev, u32 event)
> -{
> -       device_lock(&adev->dev);
> -       __acpi_nfit_notify(&adev->dev, adev->handle, event);
> -       device_unlock(&adev->dev);
> -}
> -
>  static const struct acpi_device_id acpi_nfit_ids[] = {
>         { "ACPI0012", 0 },
>         { "", 0 },
> @@ -3465,7 +3489,6 @@ static struct acpi_driver acpi_nfit_driver = {
>         .ops = {
>                 .add = acpi_nfit_add,
>                 .remove = acpi_nfit_remove,
> -               .notify = acpi_nfit_notify,
>         },
>  };
>
> --