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[V2,5/9] cpufreq: ondemand: Drop unnecessary locks from update_sampling_rate()

Message ID e0795dfc4f83b6cfeabe856dcf4e5f8f2f5b3538.1437999691.git.viresh.kumar@linaro.org
State New
Headers show

Commit Message

Viresh Kumar July 27, 2015, 12:28 p.m. UTC 
'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>
---
 drivers/cpufreq/cpufreq_ondemand.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)
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Patch

diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 2474c9c34022..f1551fc7b4fd 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -267,28 +267,20 @@  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),
 				       cpumask_of(cpu));
 
 		}
-		mutex_unlock(&dbs_info->cdbs.shared->timer_mutex);
 	}
 }