On Fri, 2023-03-17 at 18:01 +0100, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > Introduce a core thermal API function, > thermal_cooling_device_update(), > for updating the max_state value for a cooling device and rearranging > its statistics in sysfs after a possible change of its > ->get_max_state() > callback return value. > > That callback is now invoked only once, during cooling device > registration, to populate the max_state field in the cooling device > object, so if its return value changes, it needs to be invoked again > and the new return value needs to be stored as max_state. Moreover, > the statistics presented in sysfs need to be rearranged in general, > because there may not be enough room in them to store data for all > of the possible states (in the case when max_state grows). > > The new function takes care of that (and some other minor things > related to it), but some extra locking and lockdep annotations are > added in several places too to protect against crashes in the cases > when the statistics are not present or when a stale max_state value > might be used by sysfs attributes. > > Note that the actual user of the new function will be added > separately. > > Link: > https://lore.kernel.org/linux-pm/53ec1f06f61c984100868926f282647e57ecfb2d.camel@xxxxxxxxx/ > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > --- > > Rui, please have a look at this again and give it a go if > possible. It is the > only patch in the series changing in v3. Hi, Rafael, Thanks for the patch, I can confirm that it works, with ACPI passive cooling activated on my side. Tested-by: Zhang Rui <rui.zhang@xxxxxxxxx> Reviewed-by: Zhang Rui <rui.zhang@xxxxxxxxx> thanks, rui > > v2 -> v3: > Make thermal_cooling_device_update() check thermal instances > involving the > given thermal device and update the "upper" value for them if > necessary (the > "lower" and "target" values may need to be adjusted too in some > cases) to avoid > leaving thermal instances with "upper" above the new max_state of > the > corresponding cooling device. > > v1 -> v2: > * Make thermal_cooling_device_update() do the full > IS_ERR_OR_NULL() check > on cdev, so that its callers don't need to do it. > * Remove ->set_cur_state() callback invocation from > thermal_cooling_device_update(), because it is redundant (and > it doesn't > make sense to pass a state value exceeding max_state to it > anyway). > > --- > drivers/thermal/thermal_core.c | 83 > +++++++++++++++++++++++++++++++++++++++- > drivers/thermal/thermal_core.h | 2 > drivers/thermal/thermal_sysfs.c | 72 > ++++++++++++++++++++++++++++++---- > include/linux/thermal.h | 1 > 4 files changed, 149 insertions(+), 9 deletions(-) > > Index: linux-pm/drivers/thermal/thermal_core.c > =================================================================== > --- linux-pm.orig/drivers/thermal/thermal_core.c > +++ linux-pm/drivers/thermal/thermal_core.c > @@ -613,6 +613,7 @@ int thermal_zone_bind_cooling_device(str > struct thermal_instance *pos; > struct thermal_zone_device *pos1; > struct thermal_cooling_device *pos2; > + bool upper_no_limit; > int result; > > if (trip >= tz->num_trips || trip < 0) > @@ -632,7 +633,13 @@ int thermal_zone_bind_cooling_device(str > > /* lower default 0, upper default max_state */ > lower = lower == THERMAL_NO_LIMIT ? 0 : lower; > - upper = upper == THERMAL_NO_LIMIT ? cdev->max_state : upper; > + > + if (upper == THERMAL_NO_LIMIT) { > + upper = cdev->max_state; > + upper_no_limit = true; > + } else { > + upper_no_limit = false; > + } > > if (lower > upper || upper > cdev->max_state) > return -EINVAL; > @@ -644,6 +651,7 @@ int thermal_zone_bind_cooling_device(str > dev->cdev = cdev; > dev->trip = trip; > dev->upper = upper; > + dev->upper_no_limit = upper_no_limit; > dev->lower = lower; > dev->target = THERMAL_NO_TARGET; > dev->weight = weight; > @@ -1057,6 +1065,79 @@ static bool thermal_cooling_device_prese > return false; > } > > +/** > + * thermal_cooling_device_update - Update a cooling device object > + * @cdev: Target cooling device. > + * > + * Update @cdev to reflect a change of the underlying hardware or > platform. > + * > + * Must be called when the maximum cooling state of @cdev becomes > invalid and so > + * its .get_max_state() callback needs to be run to produce the new > maximum > + * cooling state value. > + */ > +void thermal_cooling_device_update(struct thermal_cooling_device > *cdev) > +{ > + struct thermal_instance *ti; > + unsigned long state; > + > + if (IS_ERR_OR_NULL(cdev)) > + return; > + > + /* > + * Hold thermal_list_lock throughout the update to prevent the > device > + * from going away while being updated. > + */ > + mutex_lock(&thermal_list_lock); > + > + if (!thermal_cooling_device_present(cdev)) > + goto unlock_list; > + > + /* > + * Update under the cdev lock to prevent the state from being > set beyond > + * the new limit concurrently. > + */ > + mutex_lock(&cdev->lock); > + > + if (cdev->ops->get_max_state(cdev, &cdev->max_state)) > + goto unlock; > + > + thermal_cooling_device_stats_reinit(cdev); > + > + list_for_each_entry(ti, &cdev->thermal_instances, cdev_node) { > + if (ti->upper == cdev->max_state) > + continue; > + > + if (ti->upper < cdev->max_state) { > + if (ti->upper_no_limit) > + ti->upper = cdev->max_state; > + > + continue; > + } > + > + ti->upper = cdev->max_state; > + if (ti->lower > ti->upper) > + ti->lower = ti->upper; > + > + if (ti->target == THERMAL_NO_TARGET) > + continue; > + > + if (ti->target > ti->upper) > + ti->target = ti->upper; > + } > + > + if (cdev->ops->get_cur_state(cdev, &state) || state > cdev- > >max_state) > + goto unlock; > + > + thermal_cooling_device_stats_update(cdev, state); > + > +unlock: > + mutex_unlock(&cdev->lock); > + > +unlock_list: > + mutex_unlock(&thermal_list_lock); > +} > +EXPORT_SYMBOL_GPL(thermal_cooling_device_update); > + > static void __unbind(struct thermal_zone_device *tz, int mask, > 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 > @@ -685,6 +685,8 @@ void thermal_cooling_device_stats_update > { > struct cooling_dev_stats *stats = cdev->stats; > > + lockdep_assert_held(&cdev->lock); > + > if (!stats) > return; > > @@ -706,13 +708,22 @@ static ssize_t total_trans_show(struct d > struct device_attribute *attr, char > *buf) > { > struct thermal_cooling_device *cdev = to_cooling_device(dev); > - struct cooling_dev_stats *stats = cdev->stats; > + struct cooling_dev_stats *stats; > int ret; > > + mutex_lock(&cdev->lock); > + > + stats = cdev->stats; > + if (!stats) > + goto unlock; > + > spin_lock(&stats->lock); > ret = sprintf(buf, "%u\n", stats->total_trans); > spin_unlock(&stats->lock); > > +unlock: > + mutex_unlock(&cdev->lock); > + > return ret; > } > > @@ -721,11 +732,18 @@ time_in_state_ms_show(struct device *dev > char *buf) > { > struct thermal_cooling_device *cdev = to_cooling_device(dev); > - struct cooling_dev_stats *stats = cdev->stats; > + struct cooling_dev_stats *stats; > ssize_t len = 0; > int i; > > + mutex_lock(&cdev->lock); > + > + stats = cdev->stats; > + if (!stats) > + goto unlock; > + > spin_lock(&stats->lock); > + > update_time_in_state(stats); > > for (i = 0; i <= cdev->max_state; i++) { > @@ -734,6 +752,9 @@ time_in_state_ms_show(struct device *dev > } > spin_unlock(&stats->lock); > > +unlock: > + mutex_unlock(&cdev->lock); > + > return len; > } > > @@ -742,8 +763,16 @@ reset_store(struct device *dev, struct d > size_t count) > { > struct thermal_cooling_device *cdev = to_cooling_device(dev); > - struct cooling_dev_stats *stats = cdev->stats; > - int i, states = cdev->max_state + 1; > + struct cooling_dev_stats *stats; > + int i, states; > + > + mutex_lock(&cdev->lock); > + > + stats = cdev->stats; > + if (!stats) > + goto unlock; > + > + states = cdev->max_state + 1; > > spin_lock(&stats->lock); > > @@ -757,6 +786,9 @@ reset_store(struct device *dev, struct d > > spin_unlock(&stats->lock); > > +unlock: > + mutex_unlock(&cdev->lock); > + > return count; > } > > @@ -764,10 +796,18 @@ static ssize_t trans_table_show(struct d > struct device_attribute *attr, char > *buf) > { > struct thermal_cooling_device *cdev = to_cooling_device(dev); > - struct cooling_dev_stats *stats = cdev->stats; > + struct cooling_dev_stats *stats; > ssize_t len = 0; > int i, j; > > + mutex_lock(&cdev->lock); > + > + stats = cdev->stats; > + if (!stats) { > + len = -ENODATA; > + goto unlock; > + } > + > len += snprintf(buf + len, PAGE_SIZE - len, " > From : To\n"); > len += snprintf(buf + len, PAGE_SIZE - len, " : "); > for (i = 0; i <= cdev->max_state; i++) { > @@ -775,8 +815,10 @@ static ssize_t trans_table_show(struct d > break; > len += snprintf(buf + len, PAGE_SIZE - len, > "state%2u ", i); > } > - if (len >= PAGE_SIZE) > - return PAGE_SIZE; > + if (len >= PAGE_SIZE) { > + len = PAGE_SIZE; > + goto unlock; > + } > > len += snprintf(buf + len, PAGE_SIZE - len, "\n"); > > @@ -799,8 +841,12 @@ static ssize_t trans_table_show(struct d > > if (len >= PAGE_SIZE) { > pr_warn_once("Thermal transition table exceeds > PAGE_SIZE. Disabling\n"); > - return -EFBIG; > + len = -EFBIG; > } > + > +unlock: > + mutex_unlock(&cdev->lock); > + > return len; > } > > @@ -830,6 +876,8 @@ static void cooling_device_stats_setup(s > unsigned long states = cdev->max_state + 1; > int var; > > + lockdep_assert_held(&cdev->lock); > + > var = sizeof(*stats); > var += sizeof(*stats->time_in_state) * states; > var += sizeof(*stats->trans_table) * states * states; > @@ -855,6 +903,8 @@ out: > > static void cooling_device_stats_destroy(struct > thermal_cooling_device *cdev) > { > + lockdep_assert_held(&cdev->lock); > + > kfree(cdev->stats); > cdev->stats = NULL; > } > @@ -879,6 +929,12 @@ void thermal_cooling_device_destroy_sysf > cooling_device_stats_destroy(cdev); > } > > +void thermal_cooling_device_stats_reinit(struct > thermal_cooling_device *cdev) > +{ > + cooling_device_stats_destroy(cdev); > + cooling_device_stats_setup(cdev); > +} > + > /* these helper will be used only at the time of bindig */ > ssize_t > trip_point_show(struct device *dev, struct device_attribute *attr, > char *buf) > Index: linux-pm/drivers/thermal/thermal_core.h > =================================================================== > --- linux-pm.orig/drivers/thermal/thermal_core.h > +++ linux-pm/drivers/thermal/thermal_core.h > @@ -101,6 +101,7 @@ struct thermal_instance { > 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) \ > @@ -127,6 +128,7 @@ int thermal_zone_create_device_groups(st > 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 > *); > Index: linux-pm/include/linux/thermal.h > =================================================================== > --- linux-pm.orig/include/linux/thermal.h > +++ linux-pm/include/linux/thermal.h > @@ -388,6 +388,7 @@ devm_thermal_of_cooling_device_register( > struct device_node *np, > char *type, void *devdata, > const struct thermal_cooling_device_ops > *ops); > +void thermal_cooling_device_update(struct thermal_cooling_device *); > void thermal_cooling_device_unregister(struct thermal_cooling_device > *); > struct thermal_zone_device *thermal_zone_get_zone_by_name(const char > *name); > int thermal_zone_get_temp(struct thermal_zone_device *tz, int > *temp); > > >
