diff mbox series

[4/8] PM / devfreq: Don't take lock in devfreq_add_device

Message ID 2fe8d1000bed5de70b08ed77fc8360d159ae4434.1568764439.git.leonard.crestez@nxp.com (mailing list archive)
State Superseded
Headers show
Series PM / devfreq: Add dev_pm_qos support | expand

Commit Message

Leonard Crestez Sept. 18, 2019, 12:18 a.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 <leonard.crestez@nxp.com>
---
 drivers/devfreq/devfreq.c | 10 ----------
 1 file changed, 10 deletions(-)

Comments

Matthias Kaehlcke Sept. 19, 2019, 12:20 a.m. UTC | #1 
On Wed, Sep 18, 2019 at 03:18:23AM +0300, Leonard Crestez wrote:
> 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 <leonard.crestez@nxp.com>
> ---
>  drivers/devfreq/devfreq.c | 10 ----------
>  1 file changed, 10 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 57a217fc92de..860cbbab476c 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -634,11 +634,10 @@ 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;
>  	INIT_LIST_HEAD(&devfreq->node);
>  	devfreq->profile = profile;
> @@ -647,28 +646,24 @@ 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;
>  
> @@ -679,20 +674,18 @@ 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 = kcalloc(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;
> @@ -701,17 +694,14 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  
>  	dev_set_name(&devfreq->dev, "devfreq%d",
>  				atomic_inc_return(&devfreq_no));
>  	err = device_register(&devfreq->dev);
>  	if (err) {
> -		mutex_unlock(&devfreq->lock);
>  		put_device(&devfreq->dev);
>  		goto err_out;
>  	}
>  
> -	mutex_unlock(&devfreq->lock);
> -
>  	mutex_lock(&devfreq_list_lock);
>  
>  	governor = try_then_request_governor(devfreq->governor_name);
>  	if (IS_ERR(governor)) {
>  		dev_err(dev, "%s: Unable to find governor for the device\n",

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
diff mbox series

Patch

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 57a217fc92de..860cbbab476c 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -634,11 +634,10 @@  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;
 	INIT_LIST_HEAD(&devfreq->node);
 	devfreq->profile = profile;
@@ -647,28 +646,24 @@  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;
 
@@ -679,20 +674,18 @@  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 = kcalloc(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;
@@ -701,17 +694,14 @@  struct devfreq *devfreq_add_device(struct device *dev,
 
 	dev_set_name(&devfreq->dev, "devfreq%d",
 				atomic_inc_return(&devfreq_no));
 	err = device_register(&devfreq->dev);
 	if (err) {
-		mutex_unlock(&devfreq->lock);
 		put_device(&devfreq->dev);
 		goto err_out;
 	}
 
-	mutex_unlock(&devfreq->lock);
-
 	mutex_lock(&devfreq_list_lock);
 
 	governor = try_then_request_governor(devfreq->governor_name);
 	if (IS_ERR(governor)) {
 		dev_err(dev, "%s: Unable to find governor for the device\n",