@@ -228,13 +228,12 @@ static void dbs_timer(struct work_struct *work)
{
struct cpu_dbs_info *cdbs = container_of(work, struct cpu_dbs_info,
dwork.work);
- struct cpu_common_dbs_info *ccdbs = cdbs->ccdbs;
- struct cpufreq_policy *policy = ccdbs->policy;
+ struct cpufreq_policy *policy = cdbs->ccdbs->policy;
struct dbs_data *dbs_data = policy->governor_data;
unsigned int sampling_rate, delay;
bool modify_all = true;
- mutex_lock(&ccdbs->timer_mutex);
+ mutex_lock(&dbs_data->cdata->mutex);
if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
@@ -252,7 +251,7 @@ static void dbs_timer(struct work_struct *work)
delay = dbs_data->cdata->gov_dbs_timer(cdbs, dbs_data, modify_all);
gov_queue_work(dbs_data, policy, delay, modify_all);
- mutex_unlock(&ccdbs->timer_mutex);
+ mutex_unlock(&dbs_data->cdata->mutex);
}
static void set_sampling_rate(struct dbs_data *dbs_data,
@@ -424,7 +423,6 @@ static int cpufreq_governor_start(struct cpufreq_policy *policy,
}
ccdbs->time_stamp = ktime_get();
- mutex_init(&ccdbs->timer_mutex);
for_each_cpu(j, policy->cpus) {
struct cpu_dbs_info *j_cdbs = cdata->get_cpu_cdbs(j);
@@ -470,8 +468,6 @@ static void cpufreq_governor_stop(struct cpufreq_policy *policy,
{
struct common_dbs_data *cdata = dbs_data->cdata;
unsigned int cpu = policy->cpu;
- struct cpu_dbs_info *cdbs = cdata->get_cpu_cdbs(cpu);
- struct cpu_common_dbs_info *ccdbs = cdbs->ccdbs;
gov_cancel_work(dbs_data, policy);
@@ -481,8 +477,6 @@ static void cpufreq_governor_stop(struct cpufreq_policy *policy,
cs_dbs_info->enable = 0;
}
-
- mutex_destroy(&ccdbs->timer_mutex);
}
static void cpufreq_governor_limits(struct cpufreq_policy *policy,
@@ -495,7 +489,6 @@ static void cpufreq_governor_limits(struct cpufreq_policy *policy,
if (!cdbs->ccdbs)
return;
- mutex_lock(&cdbs->ccdbs->timer_mutex);
if (policy->max < cdbs->ccdbs->policy->cur)
__cpufreq_driver_target(cdbs->ccdbs->policy, policy->max,
CPUFREQ_RELATION_H);
@@ -503,7 +496,6 @@ static void cpufreq_governor_limits(struct cpufreq_policy *policy,
__cpufreq_driver_target(cdbs->ccdbs->policy, policy->min,
CPUFREQ_RELATION_L);
dbs_check_cpu(dbs_data, cpu);
- mutex_unlock(&cdbs->ccdbs->timer_mutex);
}
int cpufreq_governor_dbs(struct cpufreq_policy *policy,
@@ -131,12 +131,6 @@ static void *get_cpu_dbs_info_s(int cpu) \
/* Common to all CPUs of a policy */
struct cpu_common_dbs_info {
struct cpufreq_policy *policy;
- /*
- * percpu mutex that serializes governor limit change with dbs_timer
- * invocation. We do not want dbs_timer to run when user is changing
- * the governor or limits.
- */
- struct mutex timer_mutex;
ktime_t time_stamp;
};
@@ -249,6 +249,8 @@ static void update_sampling_rate(struct dbs_data *dbs_data,
struct od_dbs_tuners *od_tuners = dbs_data->tuners;
int cpu;
+ mutex_lock(&dbs_data->cdata->mutex);
+
od_tuners->sampling_rate = new_rate = max(new_rate,
dbs_data->min_sampling_rate);
@@ -267,28 +269,21 @@ static void update_sampling_rate(struct dbs_data *dbs_data,
dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
cpufreq_cpu_put(policy);
- mutex_lock(&dbs_info->cdbs.ccdbs->timer_mutex);
-
- if (!delayed_work_pending(&dbs_info->cdbs.dwork)) {
- mutex_unlock(&dbs_info->cdbs.ccdbs->timer_mutex);
+ if (!delayed_work_pending(&dbs_info->cdbs.dwork))
continue;
- }
next_sampling = jiffies + usecs_to_jiffies(new_rate);
appointed_at = dbs_info->cdbs.dwork.timer.expires;
if (time_before(next_sampling, appointed_at)) {
- mutex_unlock(&dbs_info->cdbs.ccdbs->timer_mutex);
cancel_delayed_work_sync(&dbs_info->cdbs.dwork);
- mutex_lock(&dbs_info->cdbs.ccdbs->timer_mutex);
-
gov_queue_work(dbs_data, policy,
usecs_to_jiffies(new_rate), true);
}
- mutex_unlock(&dbs_info->cdbs.ccdbs->timer_mutex);
}
+ mutex_unlock(&dbs_data->cdata->mutex);
}
static ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
Currently the work-handler's for all the CPUs are synchronized with one another but not with cpufreq_governor_dbs(). Both work-handlers and cpufreq_governor_dbs() enqueue work. And these not being in sync is an open invitation to all kind of races to come in. So, this patch replaces 'timer_mutex' with 'cdata->mutex' so that both work-handler and callback are in sync. Also in update_sampling_rate() we are dropping the mutex while canceling delayed-work. There is no need to do that, keep lock active for the entire length of routine as that also enqueues works. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- drivers/cpufreq/cpufreq_governor.c | 14 +++----------- drivers/cpufreq/cpufreq_governor.h | 6 ------ drivers/cpufreq/cpufreq_ondemand.c | 13 ++++--------- 3 files changed, 7 insertions(+), 26 deletions(-)