We can't take a big lock around __cpufreq_governor() as this causes recursive
locking for some cases. But calls to this routine must be serialized for every
policy.
Lets introduce another variable which would guarantee serialization here.
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
drivers/cpufreq/cpufreq.c | 7 ++++++-
include/linux/cpufreq.h | 1 +
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index f320a20..4d5723db 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1692,13 +1692,15 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
policy->cpu, event);
mutex_lock(&cpufreq_governor_lock);
- if ((policy->governor_enabled && (event == CPUFREQ_GOV_START)) ||
+ if (policy->governor_busy ||
+ (policy->governor_enabled && (event == CPUFREQ_GOV_START)) ||
(!policy->governor_enabled && ((event == CPUFREQ_GOV_LIMITS) ||
(event == CPUFREQ_GOV_STOP)))) {
mutex_unlock(&cpufreq_governor_lock);
return -EBUSY;
}
+ policy->governor_busy = true;
if (event == CPUFREQ_GOV_STOP)
policy->governor_enabled = false;
else if (event == CPUFREQ_GOV_START)
@@ -1727,6 +1729,9 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
module_put(policy->governor->owner);
+ mutex_lock(&cpufreq_governor_lock);
+ policy->governor_busy = false;
+ mutex_unlock(&cpufreq_governor_lock);
return ret;
}
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index d568f39..cca885d 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -76,6 +76,7 @@ struct cpufreq_policy {
struct cpufreq_governor *governor; /* see below */
void *governor_data;
bool governor_enabled; /* governor start/stop flag */
+ bool governor_busy;
struct work_struct update; /* if update_policy() needs to be
* called, but you're in IRQ context */
--
1.7.12.rc2.18.g61b472e
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