[5/5] PM / devfreq: Don't take lock in devfreq_add_device

Commit Message

Leonard Crestez Nov. 13, 2019, 11:21 p.m. UTC

A device usually doesn't need to lock itself during initialization
because it is not yet reachable from other threads.

This simplifies the code and helps avoid recursive lock warnings.

Signed-off-by: Leonard Crestez <[e-mail]>
Reviewed-by: Matthias Kaehlcke <[e-mail]>
Reviewed-by: Chanwoo Choi <[e-mail]>
---
 drivers/devfreq/devfreq.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

Patch

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 2a035374ae74..e1ce57902391 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -684,11 +684,10 @@  struct devfreq *devfreq_add_device(struct device *dev,
 		err = -ENOMEM;
 		goto err_out;
 	}
 
 	mutex_init(&devfreq->lock);
-	mutex_lock(&devfreq->lock);
 	devfreq->dev.parent = dev;
 	devfreq->dev.class = devfreq_class;
 	devfreq->dev.release = devfreq_dev_release;
 	device_initialize(&devfreq->dev);
 	INIT_LIST_HEAD(&devfreq->node);
@@ -698,28 +697,24 @@  struct devfreq *devfreq_add_device(struct device *dev,
 	devfreq->last_status.current_frequency = profile->initial_freq;
 	devfreq->data = data;
 	devfreq->nb.notifier_call = devfreq_notifier_call;
 
 	if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
-		mutex_unlock(&devfreq->lock);
 		err = set_freq_table(devfreq);
 		if (err < 0)
 			goto err_dev;
-		mutex_lock(&devfreq->lock);
 	}
 
 	devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 	if (!devfreq->scaling_min_freq) {
-		mutex_unlock(&devfreq->lock);
 		err = -EINVAL;
 		goto err_dev;
 	}
 	devfreq->min_freq = devfreq->scaling_min_freq;
 
 	devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 	if (!devfreq->scaling_max_freq) {
-		mutex_unlock(&devfreq->lock);
 		err = -EINVAL;
 		goto err_dev;
 	}
 	devfreq->max_freq = devfreq->scaling_max_freq;
 
@@ -730,21 +725,19 @@  struct devfreq *devfreq_add_device(struct device *dev,
 			array3_size(sizeof(unsigned int),
 				    devfreq->profile->max_state,
 				    devfreq->profile->max_state),
 			GFP_KERNEL);
 	if (!devfreq->trans_table) {
-		mutex_unlock(&devfreq->lock);
 		err = -ENOMEM;
 		goto err_dev;
 	}
 
 	devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
 			devfreq->profile->max_state,
 			sizeof(unsigned long),
 			GFP_KERNEL);
 	if (!devfreq->time_in_state) {
-		mutex_unlock(&devfreq->lock);
 		err = -ENOMEM;
 		goto err_dev;
 	}
 
 	devfreq->last_stat_updated = jiffies;
@@ -752,16 +745,12 @@  struct devfreq *devfreq_add_device(struct device *dev,
 	srcu_init_notifier_head(&devfreq->transition_notifier_list);
 
 	dev_set_name(&devfreq->dev, "devfreq%d",
 				atomic_inc_return(&devfreq_no));
 	err = device_add(&devfreq->dev);
-	if (err) {
-		mutex_unlock(&devfreq->lock);
+	if (err)
 		goto err_dev;
-	}
-
-	mutex_unlock(&devfreq->lock);
 
 	mutex_lock(&devfreq_list_lock);
 
 	governor = try_then_request_governor(devfreq->governor_name);
 	if (IS_ERR(governor)) {