Re: [PATCH v2 2/9] thermal: core: Add flags to struct thermal_trip

Daniel Lezcano
2024-02-22T14:36:08Z

On 12/02/2024 19:31, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> In order to allow thermal zone creators to specify the writability of
> trip point temperature and hysteresis on a per-trip basis, add a flags
> field to struct thermal_trip and define flags to represent the desired
> trip properties.
>
> Also make thermal_zone_device_register_with_trips() set the
> THERMAL_TRIP_FLAG_RW_TEMP flag for all trips covered by the writable
> trips mask passed to it and modify the thermal sysfs code to look at
> the trip flags instead of using the writable trips mask directly or
> checking the presence of the .set_trip_hyst() zone callback.
>
> Additionally, make trip_point_temp_store() and trip_point_hyst_store()
> fail with an error code if the trip passed to one of them has
> THERMAL_TRIP_FLAG_RW_TEMP or THERMAL_TRIP_FLAG_RW_HYST,
> respectively, clear in its flags.
>
> No intentional functional impact.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>
> v1 -> v2:
> * Rename trip flags (Stanislaw).
>
> ---
> drivers/thermal/thermal_core.c | 12 +++++++++++-
> drivers/thermal/thermal_core.h | 2 +-
> drivers/thermal/thermal_sysfs.c | 28 +++++++++++++++++++---------
> include/linux/thermal.h | 7 +++++++
> 4 files changed, 38 insertions(+), 11 deletions(-)
>
> Index: linux-pm/include/linux/thermal.h
> ===================================================================
> --- linux-pm.orig/include/linux/thermal.h
> +++ linux-pm/include/linux/thermal.h
> @@ -64,15 +64,23 @@ enum thermal_notify_event {
> * @threshold: trip crossing notification threshold miliCelsius
> * @type: trip point type
> * @priv: pointer to driver data associated with this trip
> + * @flags: flags representing binary properties of the trip
> */
> struct thermal_trip {
> int temperature;
> int hysteresis;
> int threshold;
> enum thermal_trip_type type;
> + u8 flags;
> void *priv;
> };
>
> +#define THERMAL_TRIP_FLAG_RW_TEMP BIT(0)
> +#define THERMAL_TRIP_FLAG_RW_HYST BIT(1)
> +
> +#define THERMAL_TRIP_FLAG_MASK_RW (THERMAL_TRIP_FLAG_RW_TEMP | \
> + THERMAL_TRIP_FLAG_RW_HYST)

What about THERMAL_TRIP_FLAG_RW instead ?

> struct thermal_zone_device_ops {
> int (*bind) (struct thermal_zone_device *,
> struct thermal_cooling_device *);
> Index: linux-pm/drivers/thermal/thermal_core.c
> ===================================================================
> --- linux-pm.orig/drivers/thermal/thermal_core.c
> +++ linux-pm/drivers/thermal/thermal_core.c
> @@ -1356,13 +1356,23 @@ thermal_zone_device_register_with_trips(
> tz->devdata = devdata;
> tz->trips = trips;
> tz->num_trips = num_trips;
> + if (num_trips > 0) {

Is this check really necessary? for_each_trip() should exit immediately
if there is no trip points.

> + struct thermal_trip *trip;
> +
> + for_each_trip(tz, trip) {
> + if (mask & 1)
> + trip->flags |= THERMAL_TRIP_FLAG_RW_TEMP;
> +
> + mask >>= 1;
> + }
> + }
>
> thermal_set_delay_jiffies(&tz->passive_delay_jiffies, passive_delay);
> thermal_set_delay_jiffies(&tz->polling_delay_jiffies, polling_delay);
>
> /* sys I/F */
> /* Add nodes that are always present via .groups */
> - result = thermal_zone_create_device_groups(tz, mask);
> + result = thermal_zone_create_device_groups(tz);
> if (result)
> goto remove_id;
>
> Index: linux-pm/drivers/thermal/thermal_core.h
> ===================================================================
> --- linux-pm.orig/drivers/thermal/thermal_core.h
> +++ linux-pm/drivers/thermal/thermal_core.h
> @@ -131,7 +131,7 @@ void thermal_zone_trip_updated(struct th
> int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp);
>
> /* sysfs I/F */
> -int thermal_zone_create_device_groups(struct thermal_zone_device *, int);
> +int thermal_zone_create_device_groups(struct thermal_zone_device *tz);
> void thermal_zone_destroy_device_groups(struct thermal_zone_device *);
> void thermal_cooling_device_setup_sysfs(struct thermal_cooling_device *);
> void thermal_cooling_device_destroy_sysfs(struct thermal_cooling_device *cdev);
> Index: linux-pm/drivers/thermal/thermal_sysfs.c
> ===================================================================
> --- linux-pm.orig/drivers/thermal/thermal_sysfs.c
> +++ linux-pm/drivers/thermal/thermal_sysfs.c
> @@ -122,6 +122,11 @@ trip_point_temp_store(struct device *dev
>
> trip = &tz->trips[trip_id];
>
> + if (!(trip->flags & THERMAL_TRIP_FLAG_RW_TEMP)) {
> + ret = -EPERM;
> + goto unlock;
> + }

Does it really happen?

If the sysfs file is created with the right permission regarding the
trip->flags then this condition can never be true.

> if (temp != trip->temperature) {
> if (tz->ops->set_trip_temp) {
> ret = tz->ops->set_trip_temp(tz, trip_id, temp);
> @@ -173,6 +178,11 @@ trip_point_hyst_store(struct device *dev
>
> trip = &tz->trips[trip_id];
>
> + if (!(trip->flags & THERMAL_TRIP_FLAG_RW_HYST)) {
> + ret = -EPERM;
> + goto unlock;
> + }

Ditto

> if (hyst != trip->hysteresis) {
> if (tz->ops->set_trip_hyst) {
> ret = tz->ops->set_trip_hyst(tz, trip_id, hyst);
> @@ -392,17 +402,16 @@ static const struct attribute_group *the
> /**
> * create_trip_attrs() - create attributes for trip points
> * @tz: the thermal zone device
> - * @mask: Writeable trip point bitmap.
> *
> * helper function to instantiate sysfs entries for every trip
> * point and its properties of a struct thermal_zone_device.
> *
> * Return: 0 on success, the proper error value otherwise.
> */
> -static int create_trip_attrs(struct thermal_zone_device *tz, int mask)
> +static int create_trip_attrs(struct thermal_zone_device *tz)
> {
> + const struct thermal_trip *trip;
> struct attribute **attrs;
> - int indx;
>
> /* This function works only for zones with at least one trip */
> if (tz->num_trips <= 0)
> @@ -437,7 +446,9 @@ static int create_trip_attrs(struct ther
> return -ENOMEM;
> }
>
> - for (indx = 0; indx < tz->num_trips; indx++) {
> + for_each_trip(tz, trip) {
> + int indx = thermal_zone_trip_id(tz, trip);
> +
> /* create trip type attribute */
> snprintf(tz->trip_type_attrs[indx].name, THERMAL_NAME_LENGTH,
> "trip_point_%d_type", indx);
> @@ -458,7 +469,7 @@ static int create_trip_attrs(struct ther
> tz->trip_temp_attrs[indx].name;
> tz->trip_temp_attrs[indx].attr.attr.mode = S_IRUGO;
> tz->trip_temp_attrs[indx].attr.show = trip_point_temp_show;
> - if (mask & (1 << indx)) {
> + if (trip->flags & THERMAL_TRIP_FLAG_RW_TEMP) {
> tz->trip_temp_attrs[indx].attr.attr.mode |= S_IWUSR;
> tz->trip_temp_attrs[indx].attr.store =
> trip_point_temp_store;
> @@ -473,7 +484,7 @@ static int create_trip_attrs(struct ther
> tz->trip_hyst_attrs[indx].name;
> tz->trip_hyst_attrs[indx].attr.attr.mode = S_IRUGO;
> tz->trip_hyst_attrs[indx].attr.show = trip_point_hyst_show;
> - if (tz->ops->set_trip_hyst) {
> + if (trip->flags & THERMAL_TRIP_FLAG_RW_HYST) {
> tz->trip_hyst_attrs[indx].attr.attr.mode |= S_IWUSR;
> tz->trip_hyst_attrs[indx].attr.store =
> trip_point_hyst_store;
> @@ -505,8 +516,7 @@ static void destroy_trip_attrs(struct th
> kfree(tz->trips_attribute_group.attrs);
> }
>
> -int thermal_zone_create_device_groups(struct thermal_zone_device *tz,
> - int mask)
> +int thermal_zone_create_device_groups(struct thermal_zone_device *tz)
> {
> const struct attribute_group **groups;
> int i, size, result;
> @@ -522,7 +532,7 @@ int thermal_zone_create_device_groups(st
> groups[i] = thermal_zone_attribute_groups[i];
>
> if (tz->num_trips) {
> - result = create_trip_attrs(tz, mask);
> + result = create_trip_attrs(tz);
> if (result) {
> kfree(groups);
>
>
>
>

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