* [PATCH 2/2] PM: EM: Simplify mutex-related code in energy_model.c using scoped_guard
2025-12-30 6:15 [PATCH 1/2] PM: EM: Fix incorrect description of the cost field in struct em_perf_state Yaxiong Tian
@ 2025-12-30 6:20 ` Yaxiong Tian
2025-12-30 9:35 ` [PATCH 1/2] PM: EM: Fix incorrect description of the cost field in struct em_perf_state Lukasz Luba
1 sibling, 0 replies; 4+ messages in thread
From: Yaxiong Tian @ 2025-12-30 6:20 UTC (permalink / raw)
To: lukasz.luba, rafael, pavel, lenb; +Cc: linux-pm, linux-kernel, Yaxiong Tian
Code cleanup with no functional changes. Use scoped_guard() instead of
open-coded mutex_lock/mutex_unlock.
Signed-off-by: Yaxiong Tian <tianyaxiong@kylinos.cn>
---
kernel/power/energy_model.c | 173 ++++++++++++++++--------------------
1 file changed, 78 insertions(+), 95 deletions(-)
diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
index 11af9f64aa82..cf2a8e958ecb 100644
--- a/kernel/power/energy_model.c
+++ b/kernel/power/energy_model.c
@@ -333,25 +333,21 @@ int em_dev_update_perf_domain(struct device *dev,
return -EINVAL;
/* Serialize update/unregister or concurrent updates */
- mutex_lock(&em_pd_mutex);
-
- if (!dev->em_pd) {
- mutex_unlock(&em_pd_mutex);
- return -EINVAL;
- }
- pd = dev->em_pd;
-
- kref_get(&new_table->kref);
+ scoped_guard(mutex, &em_pd_mutex) {
+ if (!dev->em_pd)
+ return -EINVAL;
+ pd = dev->em_pd;
- old_table = rcu_dereference_protected(pd->em_table,
- lockdep_is_held(&em_pd_mutex));
- rcu_assign_pointer(pd->em_table, new_table);
+ kref_get(&new_table->kref);
- em_cpufreq_update_efficiencies(dev, new_table->state);
+ old_table = rcu_dereference_protected(pd->em_table,
+ lockdep_is_held(&em_pd_mutex));
+ rcu_assign_pointer(pd->em_table, new_table);
- em_table_free(old_table);
+ em_cpufreq_update_efficiencies(dev, new_table->state);
- mutex_unlock(&em_pd_mutex);
+ em_table_free(old_table);
+ }
em_notify_pd_updated(pd);
return 0;
@@ -623,82 +619,70 @@ int em_dev_register_pd_no_update(struct device *dev, unsigned int nr_states,
* Use a mutex to serialize the registration of performance domains and
* let the driver-defined callback functions sleep.
*/
- mutex_lock(&em_pd_mutex);
-
- if (dev->em_pd) {
- ret = -EEXIST;
- goto unlock;
- }
+ scoped_guard(mutex, &em_pd_mutex) {
+ if (dev->em_pd)
+ return -EEXIST;
- if (_is_cpu_device(dev)) {
- if (!cpus) {
- dev_err(dev, "EM: invalid CPU mask\n");
- ret = -EINVAL;
- goto unlock;
- }
-
- for_each_cpu(cpu, cpus) {
- if (em_cpu_get(cpu)) {
- dev_err(dev, "EM: exists for CPU%d\n", cpu);
- ret = -EEXIST;
- goto unlock;
+ if (_is_cpu_device(dev)) {
+ if (!cpus) {
+ dev_err(dev, "EM: invalid CPU mask\n");
+ return -EINVAL;
}
- /*
- * All CPUs of a domain must have the same
- * micro-architecture since they all share the same
- * table.
- */
- cap = arch_scale_cpu_capacity(cpu);
- if (prev_cap && prev_cap != cap) {
- dev_err(dev, "EM: CPUs of %*pbl must have the same capacity\n",
- cpumask_pr_args(cpus));
-
- ret = -EINVAL;
- goto unlock;
+
+ for_each_cpu(cpu, cpus) {
+ if (em_cpu_get(cpu)) {
+ dev_err(dev, "EM: exists for CPU%d\n", cpu);
+ return -EEXIST;
+ }
+ /*
+ * All CPUs of a domain must have the same
+ * micro-architecture since they all share the same
+ * table.
+ */
+ cap = arch_scale_cpu_capacity(cpu);
+ if (prev_cap && prev_cap != cap) {
+ dev_err(dev, "EM: CPUs of %*pbl must have the same capacity\n",
+ cpumask_pr_args(cpus));
+
+ return -EINVAL;
+ }
+ prev_cap = cap;
}
- prev_cap = cap;
}
- }
- if (microwatts)
- flags |= EM_PERF_DOMAIN_MICROWATTS;
- else if (cb->get_cost)
- flags |= EM_PERF_DOMAIN_ARTIFICIAL;
+ if (microwatts)
+ flags |= EM_PERF_DOMAIN_MICROWATTS;
+ else if (cb->get_cost)
+ flags |= EM_PERF_DOMAIN_ARTIFICIAL;
- /*
- * EM only supports uW (exception is artificial EM).
- * Therefore, check and force the drivers to provide
- * power in uW.
- */
- if (!microwatts && !(flags & EM_PERF_DOMAIN_ARTIFICIAL)) {
- dev_err(dev, "EM: only supports uW power values\n");
- ret = -EINVAL;
- goto unlock;
- }
-
- ret = em_create_pd(dev, nr_states, cb, cpus, flags);
- if (ret)
- goto unlock;
+ /*
+ * EM only supports uW (exception is artificial EM).
+ * Therefore, check and force the drivers to provide
+ * power in uW.
+ */
+ if (!microwatts && !(flags & EM_PERF_DOMAIN_ARTIFICIAL)) {
+ dev_err(dev, "EM: only supports uW power values\n");
+ return -EINVAL;
+ }
- dev->em_pd->flags |= flags;
- dev->em_pd->min_perf_state = 0;
- dev->em_pd->max_perf_state = nr_states - 1;
+ ret = em_create_pd(dev, nr_states, cb, cpus, flags);
+ if (ret)
+ return ret;
- em_table = rcu_dereference_protected(dev->em_pd->em_table,
- lockdep_is_held(&em_pd_mutex));
- em_cpufreq_update_efficiencies(dev, em_table->state);
+ dev->em_pd->flags |= flags;
+ dev->em_pd->min_perf_state = 0;
+ dev->em_pd->max_perf_state = nr_states - 1;
- em_debug_create_pd(dev);
- dev_info(dev, "EM: created perf domain\n");
+ em_table = rcu_dereference_protected(dev->em_pd->em_table,
+ lockdep_is_held(&em_pd_mutex));
+ em_cpufreq_update_efficiencies(dev, em_table->state);
-unlock:
- mutex_unlock(&em_pd_mutex);
- if (ret)
- return ret;
+ em_debug_create_pd(dev);
+ dev_info(dev, "EM: created perf domain\n");
+ }
- mutex_lock(&em_pd_list_mutex);
- list_add_tail(&dev->em_pd->node, &em_pd_list);
- mutex_unlock(&em_pd_list_mutex);
+ scoped_guard(mutex, &em_pd_list_mutex)
+ list_add_tail(&dev->em_pd->node, &em_pd_list);
em_notify_pd_created(dev->em_pd);
@@ -720,9 +704,8 @@ void em_dev_unregister_perf_domain(struct device *dev)
if (_is_cpu_device(dev))
return;
- mutex_lock(&em_pd_list_mutex);
- list_del_init(&dev->em_pd->node);
- mutex_unlock(&em_pd_list_mutex);
+ scoped_guard(mutex, &em_pd_list_mutex)
+ list_del_init(&dev->em_pd->node);
em_notify_pd_deleted(dev->em_pd);
@@ -731,17 +714,17 @@ void em_dev_unregister_perf_domain(struct device *dev)
* from potential clean-up/setup issues in the debugfs directories.
* The debugfs directory name is the same as device's name.
*/
- mutex_lock(&em_pd_mutex);
- em_debug_remove_pd(dev);
+ scoped_guard(mutex, &em_pd_mutex) {
+ em_debug_remove_pd(dev);
- em_table_free(rcu_dereference_protected(dev->em_pd->em_table,
- lockdep_is_held(&em_pd_mutex)));
+ em_table_free(rcu_dereference_protected(dev->em_pd->em_table,
+ lockdep_is_held(&em_pd_mutex)));
- ida_free(&em_pd_ida, dev->em_pd->id);
+ ida_free(&em_pd_ida, dev->em_pd->id);
- kfree(dev->em_pd);
- dev->em_pd = NULL;
- mutex_unlock(&em_pd_mutex);
+ kfree(dev->em_pd);
+ dev->em_pd = NULL;
+ }
}
EXPORT_SYMBOL_GPL(em_dev_unregister_perf_domain);
@@ -983,10 +966,10 @@ int em_update_performance_limits(struct em_perf_domain *pd,
/* Guard simultaneous updates and make them atomic */
- mutex_lock(&em_pd_mutex);
- pd->min_perf_state = min_ps;
- pd->max_perf_state = max_ps;
- mutex_unlock(&em_pd_mutex);
+ scoped_guard(mutex, &em_pd_mutex) {
+ pd->min_perf_state = min_ps;
+ pd->max_perf_state = max_ps;
+ }
return 0;
}
--
2.25.1
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