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linux/drivers/thermal/thermal_core.h
Rafael J. Wysocki a42a5839f4 thermal: core: Reference count the zone in thermal_zone_get_by_id() 
There are places in the thermal netlink code where nothing prevents
the thermal zone object from going away while being accessed after it
has been returned by thermal_zone_get_by_id().

To address this, make thermal_zone_get_by_id() get a reference on the
thermal zone device object to be returned with the help of get_device(),
under thermal_list_lock, and adjust all of its callers to this change
with the help of the cleanup.h infrastructure.

Fixes: 1ce50e7d40 ("thermal: core: genetlink support for events/cmd/sampling")
Cc: 6.8+ <stable@vger.kernel.org> # 6.8+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://patch.msgid.link/6112242.lOV4Wx5bFT@rjwysocki.net
2024-10-04 19:05:08 +02:00

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* thermal_core.h
*
* Copyright (C) 2012 Intel Corp
* Author: Durgadoss R <durgadoss.r@intel.com>
*/
#ifndef __THERMAL_CORE_H__
#define __THERMAL_CORE_H__
#include <linux/device.h>
#include <linux/thermal.h>
#include "thermal_netlink.h"
#include "thermal_debugfs.h"
struct thermal_attr {
struct device_attribute attr;
char name[THERMAL_NAME_LENGTH];
};
struct thermal_trip_attrs {
struct thermal_attr type;
struct thermal_attr temp;
struct thermal_attr hyst;
};
struct thermal_trip_desc {
struct thermal_trip trip;
struct thermal_trip_attrs trip_attrs;
struct list_head notify_list_node;
int notify_temp;
int threshold;
};
/**
* struct thermal_governor - structure that holds thermal governor information
* @name: name of the governor
* @bind_to_tz: callback called when binding to a thermal zone. If it
* returns 0, the governor is bound to the thermal zone,
* otherwise it fails.
* @unbind_from_tz: callback called when a governor is unbound from a
* thermal zone.
* @trip_crossed: called for trip points that have just been crossed
* @manage: called on thermal zone temperature updates
* @update_tz: callback called when thermal zone internals have changed, e.g.
* thermal cooling instance was added/removed
* @governor_list: node in thermal_governor_list (in thermal_core.c)
*/
struct thermal_governor {
const char *name;
int (*bind_to_tz)(struct thermal_zone_device *tz);
void (*unbind_from_tz)(struct thermal_zone_device *tz);
void (*trip_crossed)(struct thermal_zone_device *tz,
const struct thermal_trip *trip,
bool crossed_up);
void (*manage)(struct thermal_zone_device *tz);
void (*update_tz)(struct thermal_zone_device *tz,
enum thermal_notify_event reason);
struct list_head governor_list;
};
/**
* struct thermal_zone_device - structure for a thermal zone
* @id: unique id number for each thermal zone
* @type: the thermal zone device type
* @device: &struct device for this thermal zone
* @removal: removal completion
* @resume: resume completion
* @mode: current mode of this thermal zone
* @devdata: private pointer for device private data
* @num_trips: number of trip points the thermal zone supports
* @passive_delay_jiffies: number of jiffies to wait between polls when
* performing passive cooling.
* @polling_delay_jiffies: number of jiffies to wait between polls when
* checking whether trip points have been crossed (0 for
* interrupt driven systems)
* @recheck_delay_jiffies: delay after a failed attempt to determine the zone
* temperature before trying again
* @temperature: current temperature. This is only for core code,
* drivers should use thermal_zone_get_temp() to get the
* current temperature
* @last_temperature: previous temperature read
* @emul_temperature: emulated temperature when using CONFIG_THERMAL_EMULATION
* @passive: 1 if you've crossed a passive trip point, 0 otherwise.
* @prev_low_trip: the low current temperature if you've crossed a passive
trip point.
* @prev_high_trip: the above current temperature if you've crossed a
passive trip point.
* @need_update: if equals 1, thermal_zone_device_update needs to be invoked.
* @ops: operations this &thermal_zone_device supports
* @tzp: thermal zone parameters
* @governor: pointer to the governor for this thermal zone
* @governor_data: private pointer for governor data
* @thermal_instances: list of &struct thermal_instance of this thermal zone
* @ida: &struct ida to generate unique id for this zone's cooling
* devices
* @lock: lock to protect thermal_instances list
* @node: node in thermal_tz_list (in thermal_core.c)
* @poll_queue: delayed work for polling
* @notify_event: Last notification event
* @suspended: thermal zone suspend indicator
* @resuming: indicates whether or not thermal zone resume is in progress
* @trips: array of struct thermal_trip objects
*/
struct thermal_zone_device {
int id;
char type[THERMAL_NAME_LENGTH];
struct device device;
struct completion removal;
struct completion resume;
struct attribute_group trips_attribute_group;
enum thermal_device_mode mode;
void *devdata;
int num_trips;
unsigned long passive_delay_jiffies;
unsigned long polling_delay_jiffies;
unsigned long recheck_delay_jiffies;
int temperature;
int last_temperature;
int emul_temperature;
int passive;
int prev_low_trip;
int prev_high_trip;
atomic_t need_update;
struct thermal_zone_device_ops ops;
struct thermal_zone_params *tzp;
struct thermal_governor *governor;
void *governor_data;
struct list_head thermal_instances;
struct ida ida;
struct mutex lock;
struct list_head node;
struct delayed_work poll_queue;
enum thermal_notify_event notify_event;
bool suspended;
bool resuming;
#ifdef CONFIG_THERMAL_DEBUGFS
struct thermal_debugfs *debugfs;
#endif
struct thermal_trip_desc trips[] __counted_by(num_trips);
};
/* Initial thermal zone temperature. */
#define THERMAL_TEMP_INIT INT_MIN
/*
* Default and maximum delay after a failed thermal zone temperature check
* before attempting to check it again (in jiffies).
*/
#define THERMAL_RECHECK_DELAY msecs_to_jiffies(250)
#define THERMAL_MAX_RECHECK_DELAY (120 * HZ)
/* Default Thermal Governor */
#if defined(CONFIG_THERMAL_DEFAULT_GOV_STEP_WISE)
#define DEFAULT_THERMAL_GOVERNOR "step_wise"
#elif defined(CONFIG_THERMAL_DEFAULT_GOV_FAIR_SHARE)
#define DEFAULT_THERMAL_GOVERNOR "fair_share"
#elif defined(CONFIG_THERMAL_DEFAULT_GOV_USER_SPACE)
#define DEFAULT_THERMAL_GOVERNOR "user_space"
#elif defined(CONFIG_THERMAL_DEFAULT_GOV_POWER_ALLOCATOR)
#define DEFAULT_THERMAL_GOVERNOR "power_allocator"
#elif defined(CONFIG_THERMAL_DEFAULT_GOV_BANG_BANG)
#define DEFAULT_THERMAL_GOVERNOR "bang_bang"
#endif
/* Initial state of a cooling device during binding */
#define THERMAL_NO_TARGET -1UL
/* Init section thermal table */
extern struct thermal_governor *__governor_thermal_table[];
extern struct thermal_governor *__governor_thermal_table_end[];
#define THERMAL_TABLE_ENTRY(table, name) \
static typeof(name) *__thermal_table_entry_##name \
__used __section("__" #table "_thermal_table") = &name
#define THERMAL_GOVERNOR_DECLARE(name) THERMAL_TABLE_ENTRY(governor, name)
#define for_each_governor_table(__governor) \
for (__governor = __governor_thermal_table; \
__governor < __governor_thermal_table_end; \
__governor++)
int for_each_thermal_zone(int (*cb)(struct thermal_zone_device *, void *),
void *);
int for_each_thermal_cooling_device(int (*cb)(struct thermal_cooling_device *,
void *), void *);
int for_each_thermal_governor(int (*cb)(struct thermal_governor *, void *),
void *thermal_governor);
struct thermal_zone_device *thermal_zone_get_by_id(int id);
DEFINE_CLASS(thermal_zone_get_by_id, struct thermal_zone_device *,
if (_T) put_device(&_T->device), thermal_zone_get_by_id(id), int id)
static inline bool cdev_is_power_actor(struct thermal_cooling_device *cdev)
{
return cdev->ops->get_requested_power && cdev->ops->state2power &&
cdev->ops->power2state;
}
void thermal_cdev_update(struct thermal_cooling_device *);
void __thermal_cdev_update(struct thermal_cooling_device *cdev);
int get_tz_trend(struct thermal_zone_device *tz, const struct thermal_trip *trip);
/*
* This structure is used to describe the behavior of
* a certain cooling device on a certain trip point
* in a certain thermal zone
*/
struct thermal_instance {
int id;
char name[THERMAL_NAME_LENGTH];
struct thermal_cooling_device *cdev;
const struct thermal_trip *trip;
bool initialized;
unsigned long upper; /* Highest cooling state for this trip point */
unsigned long lower; /* Lowest cooling state for this trip point */
unsigned long target; /* expected cooling state */
char attr_name[THERMAL_NAME_LENGTH];
struct device_attribute attr;
char weight_attr_name[THERMAL_NAME_LENGTH];
struct device_attribute weight_attr;
struct list_head tz_node; /* node in tz->thermal_instances */
struct list_head cdev_node; /* node in cdev->thermal_instances */
unsigned int weight; /* The weight of the cooling device */
bool upper_no_limit;
};
#define to_thermal_zone(_dev) \
container_of(_dev, struct thermal_zone_device, device)
#define to_cooling_device(_dev) \
container_of(_dev, struct thermal_cooling_device, device)
int thermal_register_governor(struct thermal_governor *);
void thermal_unregister_governor(struct thermal_governor *);
int thermal_zone_device_set_policy(struct thermal_zone_device *, char *);
int thermal_build_list_of_policies(char *buf);
void __thermal_zone_device_update(struct thermal_zone_device *tz,
enum thermal_notify_event event);
void thermal_zone_device_critical_reboot(struct thermal_zone_device *tz);
void thermal_governor_update_tz(struct thermal_zone_device *tz,
enum thermal_notify_event reason);
/* Helpers */
#define for_each_trip_desc(__tz, __td) \
for (__td = __tz->trips; __td - __tz->trips < __tz->num_trips; __td++)
#define trip_to_trip_desc(__trip) \
container_of(__trip, struct thermal_trip_desc, trip)
const char *thermal_trip_type_name(enum thermal_trip_type trip_type);
void thermal_zone_set_trips(struct thermal_zone_device *tz, int low, int high);
int thermal_zone_trip_id(const struct thermal_zone_device *tz,
const struct thermal_trip *trip);
int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp);
void thermal_zone_trip_down(struct thermal_zone_device *tz,
const struct thermal_trip *trip);
void thermal_zone_set_trip_hyst(struct thermal_zone_device *tz,
struct thermal_trip *trip, int hyst);
/* sysfs I/F */
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);
void thermal_cooling_device_stats_reinit(struct thermal_cooling_device *cdev);
/* used only at binding time */
ssize_t trip_point_show(struct device *, struct device_attribute *, char *);
ssize_t weight_show(struct device *, struct device_attribute *, char *);
ssize_t weight_store(struct device *, struct device_attribute *, const char *,
size_t);
#ifdef CONFIG_THERMAL_STATISTICS
void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,
unsigned long new_state);
#else
static inline void
thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,
unsigned long new_state) {}
#endif /* CONFIG_THERMAL_STATISTICS */
#endif /* __THERMAL_CORE_H__ */
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