cpufreq: ondemand: Drop unnecessary locks from update_sampling_rate()

'timer_mutex' is required to sync work-handlers of policy->cpus.
update_sampling_rate() is just canceling the works and queuing them
again. This isn't protecting anything at all in update_sampling_rate()
and is not gonna be of any use.

Even if a work-handler is already running for a CPU,
cancel_delayed_work_sync() will wait for it to finish.

Drop these unnecessary locks.

Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 1fa9088..03ac6ce 100644 (file)
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -267,27 +267,19 @@ 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.shared->timer_mutex);
-
-               if (!delayed_work_pending(&dbs_info->cdbs.dwork)) {
-                       mutex_unlock(&dbs_info->cdbs.shared->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.shared->timer_mutex);
                        cancel_delayed_work_sync(&dbs_info->cdbs.dwork);
-                       mutex_lock(&dbs_info->cdbs.shared->timer_mutex);
 
                        gov_queue_work(dbs_data, policy,
                                       usecs_to_jiffies(new_rate), true);
 
                }
-               mutex_unlock(&dbs_info->cdbs.shared->timer_mutex);
        }
 }