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References: <20230708112720.2897484-1-a.fatoum@pengutronix.de>
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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Mon, 10 Jul 2023 19:33:06 +0200
Message-ID: <CAJZ5v0h6_jzOBxhmd2b8WL5nVOvZ03AD5fzdtc9ACXGiCKEmOw@mail.gmail.com>
Subject: Re: [PATCH 1/2] thermal: core: constify params in thermal_zone_device_register
To:     Ahmad Fatoum <a.fatoum@pengutronix.de>
Cc:     "Rafael J. Wysocki" <rafael@kernel.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Amit Kucheria <amitk@kernel.org>,
        Zhang Rui <rui.zhang@intel.com>, kernel@pengutronix.de,
        linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
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On Sat, Jul 8, 2023 at 1:27 PM Ahmad Fatoum <a.fatoum@pengutronix.de> wrote:
>
> Since commit 3d439b1a2ad3 ("thermal/core: Alloc-copy-free the thermal zone
> parameters structure"), thermal_zone_device_register() allocates a copy
> of the tzp argument and callers need not explicitly manage its lifetime.
>
> This means the function no longer cares about the parameter being
> mutable, so constify it.
>
> No functional change.
>
> Fixes: 3d439b1a2ad3 ("thermal/core: Alloc-copy-free the thermal zone parameters structure")

Why is this particular patch regarded as a fix?

> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  drivers/thermal/thermal_core.c | 4 ++--
>  include/linux/thermal.h        | 6 +++---
>  2 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 842f678c1c3e..cc2b5e81c620 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -1203,7 +1203,7 @@ EXPORT_SYMBOL_GPL(thermal_zone_get_crit_temp);
>  struct thermal_zone_device *
>  thermal_zone_device_register_with_trips(const char *type, struct thermal_trip *trips, int num_trips, int mask,
>                                         void *devdata, struct thermal_zone_device_ops *ops,
> -                                       struct thermal_zone_params *tzp, int passive_delay,
> +                                       const struct thermal_zone_params *tzp, int passive_delay,
>                                         int polling_delay)
>  {
>         struct thermal_zone_device *tz;
> @@ -1371,7 +1371,7 @@ EXPORT_SYMBOL_GPL(thermal_zone_device_register_with_trips);
>
>  struct thermal_zone_device *thermal_zone_device_register(const char *type, int ntrips, int mask,
>                                                          void *devdata, struct thermal_zone_device_ops *ops,
> -                                                        struct thermal_zone_params *tzp, int passive_delay,
> +                                                        const struct thermal_zone_params *tzp, int passive_delay,
>                                                          int polling_delay)
>  {
>         return thermal_zone_device_register_with_trips(type, NULL, ntrips, mask,
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index 87837094d549..dee66ade89a0 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -301,14 +301,14 @@ int thermal_acpi_critical_trip_temp(struct acpi_device *adev, int *ret_temp);
>  #ifdef CONFIG_THERMAL
>  struct thermal_zone_device *thermal_zone_device_register(const char *, int, int,
>                 void *, struct thermal_zone_device_ops *,
> -               struct thermal_zone_params *, int, int);
> +               const struct thermal_zone_params *, int, int);
>
>  void thermal_zone_device_unregister(struct thermal_zone_device *);
>
>  struct thermal_zone_device *
>  thermal_zone_device_register_with_trips(const char *, struct thermal_trip *, int, int,
>                                         void *, struct thermal_zone_device_ops *,
> -                                       struct thermal_zone_params *, int, int);
> +                                       const struct thermal_zone_params *, int, int);
>
>  void *thermal_zone_device_priv(struct thermal_zone_device *tzd);
>  const char *thermal_zone_device_type(struct thermal_zone_device *tzd);
> @@ -348,7 +348,7 @@ void thermal_zone_device_critical(struct thermal_zone_device *tz);
>  static inline struct thermal_zone_device *thermal_zone_device_register(
>         const char *type, int trips, int mask, void *devdata,
>         struct thermal_zone_device_ops *ops,
> -       struct thermal_zone_params *tzp,
> +       const struct thermal_zone_params *tzp,
>         int passive_delay, int polling_delay)
>  { return ERR_PTR(-ENODEV); }
>  static inline void thermal_zone_device_unregister(
> --
> 2.39.2
>