[PATCH 2/2] cpufreq: Only do governor start after successful stop

From: Xiaoguang Chen
Date: Tue Aug 13 2013 - 03:10:53 EST


cpufreq_add_policy_cpu, __cpufreq_remove_dev and __cpufreq_set_policy
have operations for governor stop and start.
Only do the start operation when the previous stop operation succeeds.

Signed-off-by: Xiaoguang Chen <chenxg@xxxxxxxxxxx>
---
drivers/cpufreq/cpufreq.c | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index dfe0b86..2e0b17f 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -916,7 +916,7 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling,
WARN_ON(!policy);

if (has_target)
- __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
+ ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);

lock_policy_rwsem_write(sibling);

@@ -930,7 +930,8 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling,
unlock_policy_rwsem_write(sibling);

if (has_target) {
- __cpufreq_governor(policy, CPUFREQ_GOV_START);
+ if (!ret)
+ __cpufreq_governor(policy, CPUFREQ_GOV_START);
__cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
}

@@ -1109,7 +1110,7 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
static int __cpufreq_remove_dev(struct device *dev,
struct subsys_interface *sif)
{
- unsigned int cpu = dev->id, ret, cpus;
+ unsigned int cpu = dev->id, ret, opsret = 0, cpus;
unsigned long flags;
struct cpufreq_policy *data;
struct kobject *kobj;
@@ -1131,7 +1132,7 @@ static int __cpufreq_remove_dev(struct device *dev,
}

if (cpufreq_driver->target)
- __cpufreq_governor(data, CPUFREQ_GOV_STOP);
+ opsret = __cpufreq_governor(data, CPUFREQ_GOV_STOP);

#ifdef CONFIG_HOTPLUG_CPU
if (!cpufreq_driver->setpolicy)
@@ -1206,7 +1207,8 @@ static int __cpufreq_remove_dev(struct device *dev,
pr_debug("%s: removing link, cpu: %d\n", __func__, cpu);
cpufreq_cpu_put(data);
if (cpufreq_driver->target) {
- __cpufreq_governor(data, CPUFREQ_GOV_START);
+ if (!opsret)
+ __cpufreq_governor(data, CPUFREQ_GOV_START);
__cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
}
}
@@ -1784,7 +1786,7 @@ EXPORT_SYMBOL(cpufreq_get_policy);
static int __cpufreq_set_policy(struct cpufreq_policy *data,
struct cpufreq_policy *policy)
{
- int ret = 0, failed = 1;
+ int ret = 0, failed = 1, opsret = 0;

pr_debug("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
policy->min, policy->max);
@@ -1841,7 +1843,8 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data,

/* end old governor */
if (data->governor) {
- __cpufreq_governor(data, CPUFREQ_GOV_STOP);
+ opsret = __cpufreq_governor(data,
+ CPUFREQ_GOV_STOP);
unlock_policy_rwsem_write(policy->cpu);
__cpufreq_governor(data,
CPUFREQ_GOV_POLICY_EXIT);
@@ -1851,7 +1854,8 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data,
/* start new governor */
data->governor = policy->governor;
if (!__cpufreq_governor(data, CPUFREQ_GOV_POLICY_INIT)) {
- if (!__cpufreq_governor(data, CPUFREQ_GOV_START)) {
+ if (!opsret && !__cpufreq_governor(
+ data, CPUFREQ_GOV_START)) {
failed = 0;
} else {
unlock_policy_rwsem_write(policy->cpu);
@@ -1869,8 +1873,9 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data,
data->governor = old_gov;
__cpufreq_governor(data,
CPUFREQ_GOV_POLICY_INIT);
- __cpufreq_governor(data,
- CPUFREQ_GOV_START);
+ if (!opsret)
+ __cpufreq_governor(data,
+ CPUFREQ_GOV_START);
}
ret = -EINVAL;
goto error_out;
--
1.8.0

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