'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(-)
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); } }