[PATCH] thermal: Make sysfs attributes of cooling devices default attributes

[PATCH] thermal: Make sysfs attributes of cooling devices default attributes

[Matthias Kaehlcke]

Default attributes are created when the device is registered. Attributes
created after device registration can lead to race conditions, where user space
(e.g. udev) sees the device but not the attributes.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---
 drivers/thermal/thermal_core.c | 37 +++++++++++++++++--------------------
 1 file changed, 17 insertions(+), 20 deletions(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 48491d1..174d3bc 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -899,6 +899,22 @@ thermal_cooling_device_trip_point_show(struct device *dev,
 		return sprintf(buf, "%d\n", instance->trip);
 }
 
+static struct attribute *cooling_device_attrs[] = {
+	&dev_attr_cdev_type.attr,
+	&dev_attr_max_state.attr,
+	&dev_attr_cur_state.attr,
+	NULL,
+};
+
+static const struct attribute_group cooling_device_attr_group = {
+	.attrs = cooling_device_attrs,
+};
+
+static const struct attribute_group *cooling_device_attr_groups[] = {
+	&cooling_device_attr_group,
+	NULL,
+};
+
 /* Device management */
 
 /**
@@ -1130,6 +1146,7 @@ __thermal_cooling_device_register(struct device_node *np,
 	cdev->ops = ops;
 	cdev->updated = false;
 	cdev->device.class = &thermal_class;
+	cdev->device.groups = cooling_device_attr_groups;
 	cdev->devdata = devdata;
 	dev_set_name(&cdev->device, "cooling_device%d", cdev->id);
 	result = device_register(&cdev->device);
@@ -1139,21 +1156,6 @@ __thermal_cooling_device_register(struct device_node *np,
 		return ERR_PTR(result);
 	}
 
-	/* sys I/F */
-	if (type) {
-		result = device_create_file(&cdev->device, &dev_attr_cdev_type);
-		if (result)
-			goto unregister;
-	}
-
-	result = device_create_file(&cdev->device, &dev_attr_max_state);
-	if (result)
-		goto unregister;
-
-	result = device_create_file(&cdev->device, &dev_attr_cur_state);
-	if (result)
-		goto unregister;
-
 	/* Add 'this' new cdev to the global cdev list */
 	mutex_lock(&thermal_list_lock);
 	list_add(&cdev->node, &thermal_cdev_list);
@@ -1163,11 +1165,6 @@ __thermal_cooling_device_register(struct device_node *np,
 	bind_cdev(cdev);
 
 	return cdev;
-
-unregister:
-	release_idr(&thermal_cdev_idr, &thermal_idr_lock, cdev->id);
-	device_unregister(&cdev->device);
-	return ERR_PTR(result);
 }
 
 /**
-- 
2.2.0.rc0.207.ga3a616c

Re: [PATCH] thermal: Make sysfs attributes of cooling devices default attributes

[Eduardo Valentin]

[-- Attachment #1: Type: text/plain, Size: 2691 bytes --]

On Fri, Feb 20, 2015 at 06:10:08PM -0800, Matthias Kaehlcke wrote:
> Default attributes are created when the device is registered. Attributes
> created after device registration can lead to race conditions, where user space
> (e.g. udev) sees the device but not the attributes.
> 
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>

applied into -fixes branch. Thanks.

> ---
>  drivers/thermal/thermal_core.c | 37 +++++++++++++++++--------------------
>  1 file changed, 17 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 48491d1..174d3bc 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -899,6 +899,22 @@ thermal_cooling_device_trip_point_show(struct device *dev,
>  		return sprintf(buf, "%d\n", instance->trip);
>  }
>  
> +static struct attribute *cooling_device_attrs[] = {
> +	&dev_attr_cdev_type.attr,
> +	&dev_attr_max_state.attr,
> +	&dev_attr_cur_state.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group cooling_device_attr_group = {
> +	.attrs = cooling_device_attrs,
> +};
> +
> +static const struct attribute_group *cooling_device_attr_groups[] = {
> +	&cooling_device_attr_group,
> +	NULL,
> +};
> +
>  /* Device management */
>  
>  /**
> @@ -1130,6 +1146,7 @@ __thermal_cooling_device_register(struct device_node *np,
>  	cdev->ops = ops;
>  	cdev->updated = false;
>  	cdev->device.class = &thermal_class;
> +	cdev->device.groups = cooling_device_attr_groups;
>  	cdev->devdata = devdata;
>  	dev_set_name(&cdev->device, "cooling_device%d", cdev->id);
>  	result = device_register(&cdev->device);
> @@ -1139,21 +1156,6 @@ __thermal_cooling_device_register(struct device_node *np,
>  		return ERR_PTR(result);
>  	}
>  
> -	/* sys I/F */
> -	if (type) {
> -		result = device_create_file(&cdev->device, &dev_attr_cdev_type);
> -		if (result)
> -			goto unregister;
> -	}
> -
> -	result = device_create_file(&cdev->device, &dev_attr_max_state);
> -	if (result)
> -		goto unregister;
> -
> -	result = device_create_file(&cdev->device, &dev_attr_cur_state);
> -	if (result)
> -		goto unregister;
> -
>  	/* Add 'this' new cdev to the global cdev list */
>  	mutex_lock(&thermal_list_lock);
>  	list_add(&cdev->node, &thermal_cdev_list);
> @@ -1163,11 +1165,6 @@ __thermal_cooling_device_register(struct device_node *np,
>  	bind_cdev(cdev);
>  
>  	return cdev;
> -
> -unregister:
> -	release_idr(&thermal_cdev_idr, &thermal_idr_lock, cdev->id);
> -	device_unregister(&cdev->device);
> -	return ERR_PTR(result);
>  }
>  
>  /**
> -- 
> 2.2.0.rc0.207.ga3a616c
> 

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