cpufreq: use system_wq instead of dedicated workqueues

With cmwq, there's no reason for cpufreq drivers to use separate
workqueues.  Remove the dedicated workqueues from cpufreq_conservative
and cpufreq_ondemand and use system_wq instead.  The work items are
already sync canceled on stop, so it's already guaranteed that no work
is running on module exit.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Dave Jones <davej@redhat.com>
Cc: cpufreq@vger.kernel.org

2 files changed, 6 insertions, 36 deletions

diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c
index 526bfbf69611..94284c8473b1 100644
--- a/drivers/cpufreq/cpufreq_conservative.c
+++ b/drivers/cpufreq/cpufreq_conservative.c
@@ -81,8 +81,6 @@ static unsigned int dbs_enable;	/* number of CPUs using this policy */
  */
 static DEFINE_MUTEX(dbs_mutex);
 
-static struct workqueue_struct  *kconservative_wq;
-
 static struct dbs_tuners {
         unsigned int sampling_rate;
         unsigned int sampling_down_factor;
@@ -560,7 +558,7 @@ static void do_dbs_timer(struct work_struct *work)
 
         dbs_check_cpu(dbs_info);
 
-        queue_delayed_work_on(cpu, kconservative_wq, &dbs_info->work, delay);
+        schedule_delayed_work_on(cpu, &dbs_info->work, delay);
         mutex_unlock(&dbs_info->timer_mutex);
 }
 
@@ -572,8 +570,7 @@ static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
 
         dbs_info->enable = 1;
         INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);
-        queue_delayed_work_on(dbs_info->cpu, kconservative_wq, &dbs_info->work,
-                                delay);
+        schedule_delayed_work_on(dbs_info->cpu, &dbs_info->work, delay);
 }
 
 static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
@@ -716,25 +713,12 @@ struct cpufreq_governor cpufreq_gov_conservative = {
 
 static int __init cpufreq_gov_dbs_init(void)
 {
-        int err;
-
-        kconservative_wq = create_workqueue("kconservative");
-        if (!kconservative_wq) {
-                printk(KERN_ERR "Creation of kconservative failed\n");
-                return -EFAULT;
-        }
-
-        err = cpufreq_register_governor(&cpufreq_gov_conservative);
-        if (err)
-                destroy_workqueue(kconservative_wq);
-
-        return err;
+        return cpufreq_register_governor(&cpufreq_gov_conservative);
 }
 
 static void __exit cpufreq_gov_dbs_exit(void)
 {
         cpufreq_unregister_governor(&cpufreq_gov_conservative);
-        destroy_workqueue(kconservative_wq);
 }
 
 
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index c631f27a3dcc..58aa85ea5ec6 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -104,8 +104,6 @@ static unsigned int dbs_enable;	/* number of CPUs using this policy */
  */
 static DEFINE_MUTEX(dbs_mutex);
 
-static struct workqueue_struct  *kondemand_wq;
-
 static struct dbs_tuners {
         unsigned int sampling_rate;
         unsigned int up_threshold;
@@ -667,7 +665,7 @@ static void do_dbs_timer(struct work_struct *work)
                 __cpufreq_driver_target(dbs_info->cur_policy,
                         dbs_info->freq_lo, CPUFREQ_RELATION_H);
         }
-        queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
+        schedule_delayed_work_on(cpu, &dbs_info->work, delay);
         mutex_unlock(&dbs_info->timer_mutex);
 }
 
@@ -681,8 +679,7 @@ static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
 
         dbs_info->sample_type = DBS_NORMAL_SAMPLE;
         INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);
-        queue_delayed_work_on(dbs_info->cpu, kondemand_wq, &dbs_info->work,
-                delay);
+        schedule_delayed_work_on(dbs_info->cpu, &dbs_info->work, delay);
 }
 
 static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
@@ -814,7 +811,6 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 
 static int __init cpufreq_gov_dbs_init(void)
 {
-        int err;
         cputime64_t wall;
         u64 idle_time;
         int cpu = get_cpu();
@@ -838,22 +834,12 @@ static int __init cpufreq_gov_dbs_init(void)
                         MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10);
         }
 
-        kondemand_wq = create_workqueue("kondemand");
-        if (!kondemand_wq) {
-                printk(KERN_ERR "Creation of kondemand failed\n");
-                return -EFAULT;
-        }
-        err = cpufreq_register_governor(&cpufreq_gov_ondemand);
-        if (err)
-                destroy_workqueue(kondemand_wq);
-
-        return err;
+        return cpufreq_register_governor(&cpufreq_gov_ondemand);
 }
 
 static void __exit cpufreq_gov_dbs_exit(void)
 {
         cpufreq_unregister_governor(&cpufreq_gov_ondemand);
-        destroy_workqueue(kondemand_wq);
 }