linux-kernel - Re: [PATCH v5 03/10] acpi/ac: Move handler installing logic to driver

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Date:   Fri, 30 Jun 2023 11:41:55 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     "Wilczynski, Michal" <michal.wilczynski@...el.com>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        linux-acpi@...r.kernel.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 03/10] acpi/ac: Move handler installing logic to driver

On Fri, Jun 30, 2023 at 11:39 AM Wilczynski, Michal
<michal.wilczynski@...el.com> wrote:
>
>
>
> On 6/29/2023 5:55 PM, Rafael J. Wysocki wrote:
> > 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/ac.c | 33 ++++++++++++++++++++++++---------
> >>  1 file changed, 24 insertions(+), 9 deletions(-)
> >>
> >> diff --git a/drivers/acpi/ac.c b/drivers/acpi/ac.c
> >> index 1ace70b831cd..207ee3c85bad 100644
> >> --- a/drivers/acpi/ac.c
> >> +++ b/drivers/acpi/ac.c
> >> @@ -34,7 +34,7 @@ MODULE_LICENSE("GPL");
> >>
> >>  static int acpi_ac_add(struct acpi_device *device);
> >>  static void acpi_ac_remove(struct acpi_device *device);
> >> -static void acpi_ac_notify(struct acpi_device *device, u32 event);
> >> +static void acpi_ac_notify(acpi_handle handle, u32 event, void *data);
> >>
> >>  static const struct acpi_device_id ac_device_ids[] = {
> >>         {"ACPI0003", 0},
> >> @@ -54,11 +54,9 @@ static struct acpi_driver acpi_ac_driver = {
> >>         .name = "ac",
> >>         .class = ACPI_AC_CLASS,
> >>         .ids = ac_device_ids,
> >> -       .flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
> >>         .ops = {
> >>                 .add = acpi_ac_add,
> >>                 .remove = acpi_ac_remove,
> >> -               .notify = acpi_ac_notify,
> >>                 },
> >>         .drv.pm = &acpi_ac_pm,
> >>  };
> >> @@ -128,9 +126,12 @@ static enum power_supply_property ac_props[] = {
> >>  };
> >>
> >>  /* Driver Model */
> >> -static void acpi_ac_notify(struct acpi_device *device, u32 event)
> >> +static void acpi_ac_notify(acpi_handle handle, u32 event, void *data)
> >>  {
> >> -       struct acpi_ac *ac = acpi_driver_data(device);
> > This line doesn't need to be changed.  Just add the device variable
> > definition above it.
> >
> > And the same pattern is present in the other patches in the series.
>
> I like the Reverse Christmas Tree, but sure will change that

I do too, but in the cases when it costs 3 extra lines of code I'd
rather have something simpler.