Re: [PATCH v3 6/8] ACPI: thermal: Use trip point table to register thermal zones

[Rafael J. Wysocki]

On Tuesday, July 25, 2023 2:20:57 PM CEST Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> 
> Make the ACPI thermal driver use thermal_zone_device_register_with_trips()
> to register its thermal zones.
> 
> For this purpose, make it create a trip point table and pass it to
> thermal_zone_device_register_with_trips() as an argument and use the
> struct thermal_trip_ref introduced previously to connect the generic
> thermal trip structures to the internal data structures representing
> trip points in the driver.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> ---
> 
> v2 -> v3:
>    * Fix error code path memory leak in acpi_thermal_register_thermal_zone().
>    * Notice that the critical and hot trips never change after initialization,
>      so don't add struct thermal_trip_ref to any of them.
> 
> v1 -> v2:
>    * Use thermal_zone_device_lock()/thermal_zone_device_unlock() in
>      acpi_thermal_check_fn() explicitly and call __thermal_zone_device_update()
>      from there without unlocking the thermal zone.
>    * Export __thermal_zone_device_update() to modules (so it can be called by
>      the ACPI thermal code).
> 
> ---
>  drivers/acpi/thermal.c         |  106 ++++++++++++++++++++++++++++++++++++++---
>  drivers/thermal/thermal_core.c |    1 
>  include/linux/thermal.h        |    2 
>  3 files changed, 102 insertions(+), 7 deletions(-)
> 
> Index: linux-pm/drivers/acpi/thermal.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/thermal.c
> +++ linux-pm/drivers/acpi/thermal.c
> @@ -107,6 +107,7 @@ struct acpi_thermal_hot {
>  };
>  
>  struct acpi_thermal_passive {
> +	struct thermal_trip_ref trip_ref;
>  	struct acpi_handle_list devices;
>  	unsigned long temperature;
>  	unsigned long tc1;
> @@ -116,6 +117,7 @@ struct acpi_thermal_passive {
>  };
>  
>  struct acpi_thermal_active {
> +	struct thermal_trip_ref trip_ref;
>  	struct acpi_handle_list devices;
>  	unsigned long temperature;
>  	bool valid;
> @@ -137,6 +139,7 @@ struct acpi_thermal {
>  	unsigned long polling_frequency;
>  	volatile u8 zombie;
>  	struct acpi_thermal_trips trips;
> +	struct thermal_trip *trip_table;
>  	struct acpi_handle_list devices;
>  	struct thermal_zone_device *thermal_zone;
>  	int kelvin_offset;	/* in millidegrees */
> @@ -190,6 +193,14 @@ static int acpi_thermal_get_polling_freq
>  	return 0;
>  }
>  
> +static void acpi_thermal_trip_update_temp(struct acpi_thermal *tz,
> +					  struct thermal_trip *trip,
> +					  long temperature)
> +{
> +	trip->temperature = deci_kelvin_to_millicelsius_with_offset(temperature,
> +								    tz->kelvin_offset);
> +}
> +
>  static void __acpi_thermal_trips_update(struct acpi_thermal *tz, int flag)
>  {
>  	acpi_status status;
> @@ -756,6 +767,7 @@ static void acpi_thermal_zone_sysfs_remo
>  
>  static int acpi_thermal_register_thermal_zone(struct acpi_thermal *tz)
>  {
> +	struct thermal_trip *trip;
>  	int passive_delay = 0;
>  	int trip_count = 0;
>  	int result;
> @@ -776,12 +788,54 @@ static int acpi_thermal_register_thermal
>  	for (i = 0; i < ACPI_THERMAL_MAX_ACTIVE && tz->trips.active[i].valid; i++)
>  		trip_count++;
>  
> -	tz->thermal_zone = thermal_zone_device_register("acpitz", trip_count, 0,
> -							tz, &acpi_thermal_zone_ops,
> -							NULL, passive_delay,
> -							tz->polling_frequency * 100);
> -	if (IS_ERR(tz->thermal_zone))
> -		return -ENODEV;
> +	trip = kcalloc(trip_count, sizeof(*trip), GFP_KERNEL);
> +	if (!trip)
> +		return -ENOMEM;
> +
> +	tz->trip_table = trip;
> +
> +	if (tz->trips.critical.valid) {
> +		trip->type = THERMAL_TRIP_CRITICAL;
> +		acpi_thermal_trip_update_temp(tz, trip,
> +					      tz->trips.critical.temperature);
> +		trip++;
> +	}
> +
> +	if (tz->trips.hot.valid) {
> +		trip->type = THERMAL_TRIP_HOT;
> +		acpi_thermal_trip_update_temp(tz, trip,
> +					      tz->trips.hot.temperature);
> +		trip++;
> +	}
> +
> +	if (tz->trips.passive.valid) {
> +		trip->type = THERMAL_TRIP_PASSIVE;
> +		acpi_thermal_trip_update_temp(tz, trip,
> +					      tz->trips.passive.temperature);
> +		trip->driver_ref = &tz->trips.passive.trip_ref;
> +		trip++;
> +	}
> +
> +	for (i = 0; i < ACPI_THERMAL_MAX_ACTIVE && tz->trips.active[i].valid; i++) {
> +		trip->type = THERMAL_TRIP_ACTIVE;
> +		acpi_thermal_trip_update_temp(tz, trip,
> +					      tz->trips.active[i].temperature);
> +		trip->driver_ref = &tz->trips.active[i].trip_ref;
> +		trip++;
> +	}
> +
> +	tz->thermal_zone = thermal_zone_device_register_with_trips("acpitz",
> +								   tz->trip_table,
> +								   trip_count,
> +								   0, tz,
> +								   &acpi_thermal_zone_ops,
> +								   NULL,
> +								   passive_delay,
> +								   tz->polling_frequency * 100);
> +	if (IS_ERR(tz->thermal_zone)) {
> +		result = PTR_ERR(tz->thermal_zone);
> +		goto free_trip_table;
> +	}
>  
>  	result = acpi_thermal_zone_sysfs_add(tz);
>  	if (result)
> @@ -809,6 +863,8 @@ remove_links:
>  	acpi_thermal_zone_sysfs_remove(tz);
>  unregister_tzd:
>  	thermal_zone_device_unregister(tz->thermal_zone);
> +free_trip_table:
> +	kfree(tz->trip_table);
>  
>  	return result;
>  }
> @@ -817,6 +873,7 @@ static void acpi_thermal_unregister_ther
>  {
>  	acpi_thermal_zone_sysfs_remove(tz);
>  	thermal_zone_device_unregister(tz->thermal_zone);
> +	kfree(tz->trip_table);
>  	tz->thermal_zone = NULL;
>  	acpi_bus_detach_private_data(tz->device->handle);
>  }
> @@ -950,6 +1007,9 @@ static void acpi_thermal_check_fn(struct
>  {
>  	struct acpi_thermal *tz = container_of(work, struct acpi_thermal,
>  					       thermal_check_work);
> +	struct thermal_trip *trip;
> +	long temperature;
> +	int i;
>  
>  	/*
>  	 * In general, it is not sufficient to check the pending bit, because
> @@ -964,7 +1024,39 @@ static void acpi_thermal_check_fn(struct
>  
>  	mutex_lock(&tz->thermal_check_lock);
>  
> -	thermal_zone_device_update(tz->thermal_zone, THERMAL_EVENT_UNSPECIFIED);
> +	thermal_zone_device_lock(tz->thermal_zone);
> +
> +	trip = tz->trips.passive.trip_ref.trip;
> +	if (trip) {
> +		/*
> +		 * This means that the passive trip was valid initially, so
> +		 * update its temperature in case it has changed or the trip
> +		 * has become invalid.
> +		 */
> +		temperature = tz->trips.passive.valid ?
> +				tz->trips.passive.temperature :
> +				THERMAL_TEMP_INVALID;
> +		acpi_thermal_trip_update_temp(tz, trip, temperature);

This is a mistake, because THERMAL_TEMP_INVALID should not be passed to
acpi_thermal_trip_update_temp() (and same below).

I'll send an update of this patch in a moment.

> +	}
> +
> +	for (i = 0; i < ACPI_THERMAL_MAX_ACTIVE; i++) {
> +		trip = tz->trips.active[i].trip_ref.trip;
> +		if (trip) {
> +			/*
> +			 * This means that the active trip #i was valid
> +			 * initially, so update its temperature in case it has
> +			 * changed or the trip has become invalid.
> +			 */
> +			temperature = tz->trips.active[i].valid ?
> +					tz->trips.active[i].temperature :
> +					THERMAL_TEMP_INVALID;
> +			acpi_thermal_trip_update_temp(tz, trip, temperature);
> +		}
> +	}
> +
> +	__thermal_zone_device_update(tz->thermal_zone, THERMAL_EVENT_UNSPECIFIED);
> +
> +	thermal_zone_device_unlock(tz->thermal_zone);
>  
>  	refcount_inc(&tz->thermal_check_count);
>  
> Index: linux-pm/drivers/thermal/thermal_core.c
> ===================================================================
> --- linux-pm.orig/drivers/thermal/thermal_core.c
> +++ linux-pm/drivers/thermal/thermal_core.c
> @@ -429,6 +429,7 @@ void __thermal_zone_device_update(struct
>  
>  	monitor_thermal_zone(tz);
>  }
> +EXPORT_SYMBOL_GPL(__thermal_zone_device_update);
>  
>  static int thermal_zone_device_set_mode(struct thermal_zone_device *tz,
>  					enum thermal_device_mode mode)
> Index: linux-pm/include/linux/thermal.h
> ===================================================================
> --- linux-pm.orig/include/linux/thermal.h
> +++ linux-pm/include/linux/thermal.h
> @@ -334,6 +334,8 @@ int thermal_zone_bind_cooling_device(str
>  				     unsigned int);
>  int thermal_zone_unbind_cooling_device(struct thermal_zone_device *, int,
>  				       struct thermal_cooling_device *);
> +void __thermal_zone_device_update(struct thermal_zone_device *,
> +				  enum thermal_notify_event);
>  void thermal_zone_device_update(struct thermal_zone_device *,
>  				enum thermal_notify_event);
>  void thermal_zone_device_lock(struct thermal_zone_device *tz);
>