[PATCH v2 09/11] thermal: core: Add and use cooling device guard

From: Rafael J. Wysocki
Date: Thu Oct 10 2024 - 18:24:04 EST

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From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Add and use a special guard for cooling devices.

This allows quite a few error code paths to be simplified among
other things and brings in code size reduction for a good measure.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---

This is a new iteration of

https://lore.kernel.org/linux-pm/1890654.atdPhlSkOF@xxxxxxxxxxxxx/

v1 -> v2: Rearrange cur_state_store()

---
drivers/thermal/gov_power_allocator.c | 21 +++++++--------
drivers/thermal/gov_step_wise.c | 6 ++--
drivers/thermal/thermal_core.c | 17 +++---------
drivers/thermal/thermal_debugfs.c | 25 +++++++++++-------
drivers/thermal/thermal_helpers.c | 19 +++-----------
drivers/thermal/thermal_sysfs.c | 45 ++++++++++++----------------------
include/linux/thermal.h | 3 ++
7 files changed, 57 insertions(+), 79 deletions(-)

Index: linux-pm/drivers/thermal/thermal_core.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_core.c
+++ linux-pm/drivers/thermal/thermal_core.c
@@ -756,12 +756,10 @@ static int thermal_instance_add(struct t

list_add_tail(&new_instance->trip_node, &td->thermal_instances);

- mutex_lock(&cdev->lock);
+ guard(cooling_dev)(cdev);

list_add_tail(&new_instance->cdev_node, &cdev->thermal_instances);

- mutex_unlock(&cdev->lock);
-
return 0;
}

@@ -870,11 +868,9 @@ static void thermal_instance_delete(stru
{
list_del(&instance->trip_node);

- mutex_lock(&instance->cdev->lock);
+ guard(cooling_dev)(instance->cdev);

list_del(&instance->cdev_node);
-
- mutex_unlock(&instance->cdev->lock);
}

/**
@@ -1237,10 +1233,10 @@ void thermal_cooling_device_update(struc
* Update under the cdev lock to prevent the state from being set beyond
* the new limit concurrently.
*/
- mutex_lock(&cdev->lock);
+ guard(cooling_dev)(cdev);

if (cdev->ops->get_max_state(cdev, &cdev->max_state))
- goto unlock;
+ return;

thermal_cooling_device_stats_reinit(cdev);

@@ -1267,12 +1263,9 @@ void thermal_cooling_device_update(struc
}

if (cdev->ops->get_cur_state(cdev, &state) || state > cdev->max_state)
- goto unlock;
+ return;

thermal_cooling_device_stats_update(cdev, state);
-
-unlock:
- mutex_unlock(&cdev->lock);
}
EXPORT_SYMBOL_GPL(thermal_cooling_device_update);

Index: linux-pm/include/linux/thermal.h
===================================================================
--- linux-pm.orig/include/linux/thermal.h
+++ linux-pm/include/linux/thermal.h
@@ -137,6 +137,9 @@ struct thermal_cooling_device {
#endif
};

+DEFINE_GUARD(cooling_dev, struct thermal_cooling_device *, mutex_lock(&_T->lock),
+ mutex_unlock(&_T->lock))
+
/* Structure to define Thermal Zone parameters */
struct thermal_zone_params {
const char *governor_name;
Index: linux-pm/drivers/thermal/thermal_sysfs.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_sysfs.c
+++ linux-pm/drivers/thermal/thermal_sysfs.c
@@ -544,14 +544,15 @@ cur_state_store(struct device *dev, stru
if (state > cdev->max_state)
return -EINVAL;

- mutex_lock(&cdev->lock);
+ guard(cooling_dev)(cdev);

result = cdev->ops->set_cur_state(cdev, state);
- if (!result)
- thermal_cooling_device_stats_update(cdev, state);
+ if (result)
+ return result;

- mutex_unlock(&cdev->lock);
- return result ? result : count;
+ thermal_cooling_device_stats_update(cdev, state);
+
+ return count;
}

static struct device_attribute
@@ -625,21 +626,18 @@ static ssize_t total_trans_show(struct d
{
struct thermal_cooling_device *cdev = to_cooling_device(dev);
struct cooling_dev_stats *stats;
- int ret = 0;
+ int ret;

- mutex_lock(&cdev->lock);
+ guard(cooling_dev)(cdev);

stats = cdev->stats;
if (!stats)
- goto unlock;
+ return 0;

spin_lock(&stats->lock);
ret = sprintf(buf, "%u\n", stats->total_trans);
spin_unlock(&stats->lock);

-unlock:
- mutex_unlock(&cdev->lock);
-
return ret;
}

@@ -652,11 +650,11 @@ time_in_state_ms_show(struct device *dev
ssize_t len = 0;
int i;

- mutex_lock(&cdev->lock);
+ guard(cooling_dev)(cdev);

stats = cdev->stats;
if (!stats)
- goto unlock;
+ return 0;

spin_lock(&stats->lock);

@@ -668,9 +666,6 @@ time_in_state_ms_show(struct device *dev
}
spin_unlock(&stats->lock);

-unlock:
- mutex_unlock(&cdev->lock);
-
return len;
}

@@ -682,11 +677,11 @@ reset_store(struct device *dev, struct d
struct cooling_dev_stats *stats;
int i, states;

- mutex_lock(&cdev->lock);
+ guard(cooling_dev)(cdev);

stats = cdev->stats;
if (!stats)
- goto unlock;
+ return count;

states = cdev->max_state + 1;

@@ -702,9 +697,6 @@ reset_store(struct device *dev, struct d

spin_unlock(&stats->lock);

-unlock:
- mutex_unlock(&cdev->lock);
-
return count;
}

@@ -716,13 +708,11 @@ static ssize_t trans_table_show(struct d
ssize_t len = 0;
int i, j;

- mutex_lock(&cdev->lock);
+ guard(cooling_dev)(cdev);

stats = cdev->stats;
- if (!stats) {
- len = -ENODATA;
- goto unlock;
- }
+ if (!stats)
+ return -ENODATA;

len += snprintf(buf + len, PAGE_SIZE - len, " From : To\n");
len += snprintf(buf + len, PAGE_SIZE - len, " : ");
@@ -760,9 +750,6 @@ static ssize_t trans_table_show(struct d
len = -EFBIG;
}

-unlock:
- mutex_unlock(&cdev->lock);
-
return len;
}

Index: linux-pm/drivers/thermal/thermal_helpers.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_helpers.c
+++ linux-pm/drivers/thermal/thermal_helpers.c
@@ -58,17 +58,10 @@ bool thermal_trip_is_bound_to_cdev(struc
const struct thermal_trip *trip,
struct thermal_cooling_device *cdev)
{
- bool ret;
-
guard(thermal_zone)(tz);
+ guard(cooling_dev)(cdev);

- mutex_lock(&cdev->lock);
-
- ret = thermal_instance_present(tz, cdev, trip);
-
- mutex_unlock(&cdev->lock);
-
- return ret;
+ return thermal_instance_present(tz, cdev, trip);
}
EXPORT_SYMBOL_GPL(thermal_trip_is_bound_to_cdev);

@@ -197,12 +190,12 @@ void __thermal_cdev_update(struct therma
*/
void thermal_cdev_update(struct thermal_cooling_device *cdev)
{
- mutex_lock(&cdev->lock);
+ guard(cooling_dev)(cdev);
+
if (!cdev->updated) {
__thermal_cdev_update(cdev);
cdev->updated = true;
}
- mutex_unlock(&cdev->lock);
}

/**
@@ -211,11 +204,9 @@ void thermal_cdev_update(struct thermal_
*/
void thermal_cdev_update_nocheck(struct thermal_cooling_device *cdev)
{
- mutex_lock(&cdev->lock);
+ guard(cooling_dev)(cdev);

__thermal_cdev_update(cdev);
-
- mutex_unlock(&cdev->lock);
}

/**
Index: linux-pm/drivers/thermal/thermal_debugfs.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_debugfs.c
+++ linux-pm/drivers/thermal/thermal_debugfs.c
@@ -516,6 +516,19 @@ void thermal_debug_cdev_add(struct therm
cdev->debugfs = thermal_dbg;
}

+static struct thermal_debugfs *thermal_debug_cdev_clear(struct thermal_cooling_device *cdev)
+{
+ struct thermal_debugfs *thermal_dbg;
+
+ guard(cooling_dev)(cdev);
+
+ thermal_dbg = cdev->debugfs;
+ if (thermal_dbg)
+ cdev->debugfs = NULL;
+
+ return thermal_dbg;
+}
+
/**
* thermal_debug_cdev_remove - Remove a cooling device debugfs entry
*
@@ -527,17 +540,9 @@ void thermal_debug_cdev_remove(struct th
{
struct thermal_debugfs *thermal_dbg;

- mutex_lock(&cdev->lock);
-
- thermal_dbg = cdev->debugfs;
- if (!thermal_dbg) {
- mutex_unlock(&cdev->lock);
+ thermal_dbg = thermal_debug_cdev_clear(cdev);
+ if (!thermal_dbg)
return;
- }
-
- cdev->debugfs = NULL;
-
- mutex_unlock(&cdev->lock);

mutex_lock(&thermal_dbg->lock);

Index: linux-pm/drivers/thermal/gov_power_allocator.c
===================================================================
--- linux-pm.orig/drivers/thermal/gov_power_allocator.c
+++ linux-pm/drivers/thermal/gov_power_allocator.c
@@ -549,18 +549,17 @@ static void allow_maximum_power(struct t
cdev = instance->cdev;

instance->target = 0;
- mutex_lock(&cdev->lock);
- /*
- * Call for updating the cooling devices local stats and avoid
- * periods of dozen of seconds when those have not been
- * maintained.
- */
- cdev->ops->get_requested_power(cdev, &req_power);
+ scoped_guard(cooling_dev, cdev) {
+ /*
+ * Call for updating the cooling devices local stats and
+ * avoid periods of dozen of seconds when those have not
+ * been maintained.
+ */
+ cdev->ops->get_requested_power(cdev, &req_power);

- if (params->update_cdevs)
- __thermal_cdev_update(cdev);
-
- mutex_unlock(&cdev->lock);
+ if (params->update_cdevs)
+ __thermal_cdev_update(cdev);
+ }
}
}

Index: linux-pm/drivers/thermal/gov_step_wise.c
===================================================================
--- linux-pm.orig/drivers/thermal/gov_step_wise.c
+++ linux-pm/drivers/thermal/gov_step_wise.c
@@ -97,9 +97,9 @@ static void thermal_zone_trip_update(str

instance->initialized = true;

- mutex_lock(&instance->cdev->lock);
- instance->cdev->updated = false; /* cdev needs update */
- mutex_unlock(&instance->cdev->lock);
+ scoped_guard(cooling_dev, instance->cdev) {
+ instance->cdev->updated = false; /* cdev needs update */
+ }
}
}

Next message: Rafael J. Wysocki: " [PATCH v2 10/11] thermal: core: Separate thermal zone governor initialization"
Previous message: Rafael J. Wysocki: " [PATCH v2 04/11] thermal: core: Manage thermal_list_lock using a mutex guard"
In reply to: Rafael J. Wysocki: " [PATCH v2 04/11] thermal: core: Manage thermal_list_lock using a mutex guard"
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