linux-kernel - Re: [PATCH v1 02/13] ACPI: thermal: Collapse trip devices update functions

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Date:   Tue, 26 Sep 2023 20:04:34 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux PM <linux-pm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux ACPI <linux-acpi@...r.kernel.org>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Zhang Rui <rui.zhang@...el.com>,
        Lukasz Luba <lukasz.luba@....com>
Subject: Re: [PATCH v1 02/13] ACPI: thermal: Collapse trip devices update functions

On Tue, Sep 26, 2023 at 7:56 PM Rafael J. Wysocki <rafael@...nel.org> wrote:
>
> On Tue, Sep 26, 2023 at 7:18 PM Daniel Lezcano
> <daniel.lezcano@...aro.org> wrote:
> >
> > On 21/09/2023 19:49, Rafael J. Wysocki wrote:
> > > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > >
> > > In order to reduce code duplication, merge update_passive_devices() and
> > > update_active_devices() into one function called update_trip_devices()
> > > that will be used for updating both the passive and active trip points.
> > >
> > > No intentional functional impact.
> > >
> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > > ---
> > >   drivers/acpi/thermal.c |   53 ++++++++++++++++++-------------------------------
> > >   1 file changed, 20 insertions(+), 33 deletions(-)
> > >
> > > Index: linux-pm/drivers/acpi/thermal.c
> > > ===================================================================
> > > --- linux-pm.orig/drivers/acpi/thermal.c
> > > +++ linux-pm/drivers/acpi/thermal.c
> > > @@ -43,6 +43,8 @@
> > >   #define ACPI_THERMAL_MAX_ACTIVE             10
> > >   #define ACPI_THERMAL_MAX_LIMIT_STR_LEN      65
> > >
> > > +#define ACPI_THERMAL_TRIP_PASSIVE    (-1)
> > > +
> > >   /*
> > >    * This exception is thrown out in two cases:
> > >    * 1.An invalid trip point becomes invalid or a valid trip point becomes invalid
> > > @@ -202,18 +204,25 @@ static void acpi_thermal_update_passive_
> > >               ACPI_THERMAL_TRIPS_EXCEPTION(tz, "state");
> > >   }
> > >
> > > -static bool update_passive_devices(struct acpi_thermal *tz, bool compare)
> > > +static bool update_trip_devices(struct acpi_thermal *tz,
> > > +                             struct acpi_thermal_trip *acpi_trip,
> > > +                             int index, bool compare)
> > >   {
> > > -     struct acpi_thermal_trip *acpi_trip = &tz->trips.passive.trip;
> > >       struct acpi_handle_list devices;
> > > +     char method[] = "_PSL";
> > >       acpi_status status;
> > >
> > > +     if (index != ACPI_THERMAL_TRIP_PASSIVE) {
> > > +             method[1] = 'A';
> > > +             method[2] = 'L';
> > > +             method[3] = '0' + index;
> > > +     }
> >
> > Could be index > 9 ?
>
> I can add a check, but it will never be called with index > 9 anyway.

To be more precise, update_trip_devices() is called in two places,
acpi_thermal_init_trip() and acpi_thermal_update_trip_devices().

Both of these are called either with ACPI_THERMAL_TRIP_PASSIVE passed
as index, or from a loop over indices between 0 and
ACPI_THERMAL_MAX_ACTIVE-1 inclusive.