Re: [PATCH 3/8] Thermal: Add APIs to bind cdev to new zone structure

[Eduardo Valentin <eduardo.valentin@ti.com>]

Durga,

On 05-02-2013 06:46, Durgadoss R wrote:
> This patch creates new APIs to add/remove a
> cdev to/from a zone. This patch does not change
> the old cooling device implementation.

Same comments on patch 02/08 I want to rise here:

- Consider using linked list
- You may have contention on your index/cdevs array
- overflow on your buffer (carefully check your implementation)
- zone removal condition. can we remove zones with cdevs registered?
- get_by_name, why do we need it? (at least not on this patch)
- Minors on strlcpy, snprintf, devm_ helpers
- documentation in the code for these helper functions and also better 
naming..

>
> Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
> ---
>   drivers/thermal/thermal_sys.c |   80 +++++++++++++++++++++++++++++++++++++++++
>   include/linux/thermal.h       |    9 +++++
>   2 files changed, 89 insertions(+)
>
> diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
> index 838d4fb..bf703b1 100644
> --- a/drivers/thermal/thermal_sys.c
> +++ b/drivers/thermal/thermal_sys.c
> @@ -57,6 +57,7 @@ static LIST_HEAD(thermal_governor_list);
>   static DEFINE_MUTEX(thermal_list_lock);
>   static DEFINE_MUTEX(sensor_list_lock);
>   static DEFINE_MUTEX(zone_list_lock);
> +static DEFINE_MUTEX(cdev_list_lock);
>   static DEFINE_MUTEX(thermal_governor_lock);
>
>   #define for_each_thermal_sensor(pos) \
> @@ -83,6 +84,9 @@ static DEFINE_MUTEX(thermal_governor_lock);
>   	ret;						\
>   })
>
> +#define for_each_cdev(pos) \
> +	list_for_each_entry(pos, &thermal_cdev_list, node)
> +
>   static struct thermal_governor *__find_governor(const char *name)
>   {
>   	struct thermal_governor *pos;
> @@ -466,6 +470,24 @@ static void remove_sensor_from_zone(struct thermal_zone *tz,
>   	tz->sensor_indx--;
>   }
>
> +static void remove_cdev_from_zone(struct thermal_zone *tz,
> +				struct thermal_cooling_device *cdev)
> +{
> +	int j, indx;
> +
> +	indx = GET_INDEX(tz, cdev, cdev);
> +	if (indx < 0)
> +		return;
> +
> +	sysfs_remove_link(&tz->device.kobj, kobject_name(&cdev->device.kobj));
> +
> +	/* Shift the entries in the tz->cdevs array */
> +	for (j = indx; j < MAX_CDEVS_PER_ZONE - 1; j++)
> +		tz->cdevs[j] = tz->cdevs[j + 1];
> +
> +	tz->cdev_indx--;
> +}
> +
>   /* sys I/F for thermal zone */
>
>   #define to_thermal_zone(_dev) \
> @@ -1462,6 +1484,7 @@ void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
>   	int i;
>   	const struct thermal_zone_params *tzp;
>   	struct thermal_zone_device *tz;
> +	struct thermal_zone *tmp_tz;
>   	struct thermal_cooling_device *pos = NULL;
>
>   	if (!cdev)
> @@ -1499,6 +1522,13 @@ void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
>
>   	mutex_unlock(&thermal_list_lock);
>
> +	mutex_lock(&zone_list_lock);
> +
> +	for_each_thermal_zone(tmp_tz)
> +		remove_cdev_from_zone(tmp_tz, cdev);
> +
> +	mutex_unlock(&zone_list_lock);
> +
>   	if (cdev->type[0])
>   		device_remove_file(&cdev->device, &dev_attr_cdev_type);
>   	device_remove_file(&cdev->device, &dev_attr_max_state);
> @@ -1794,6 +1824,23 @@ exit:
>   }
>   EXPORT_SYMBOL(remove_thermal_zone);
>
> +struct thermal_cooling_device *get_cdev_by_name(const char *name)
> +{
> +	struct thermal_cooling_device *pos;
> +	struct thermal_cooling_device *cdev = NULL;
> +
> +	mutex_lock(&cdev_list_lock);
> +	for_each_cdev(pos) {
> +		if (!strnicmp(pos->type, name, THERMAL_NAME_LENGTH)) {
> +			cdev = pos;
> +			break;
> +		}
> +	}
> +	mutex_unlock(&cdev_list_lock);
> +	return cdev;
> +}
> +EXPORT_SYMBOL(get_cdev_by_name);
> +
>   struct thermal_sensor *get_sensor_by_name(const char *name)
>   {
>   	struct thermal_sensor *pos;
> @@ -1844,6 +1891,39 @@ exit_zone:
>   }
>   EXPORT_SYMBOL(add_sensor_to_zone);
>
> +int add_cdev_to_zone(struct thermal_zone *tz,
> +			struct thermal_cooling_device *cdev)
> +{
> +	int ret;
> +
> +	if (!tz || !cdev)
> +		return -EINVAL;
> +
> +	mutex_lock(&zone_list_lock);
> +
> +	/* Ensure we are not adding the same cdev again!! */
> +	ret = GET_INDEX(tz, cdev, cdev);
> +	if (ret >= 0) {
> +		ret = -EEXIST;
> +		goto exit_zone;
> +	}
> +
> +	mutex_lock(&cdev_list_lock);
> +	ret = sysfs_create_link(&tz->device.kobj, &cdev->device.kobj,
> +				kobject_name(&cdev->device.kobj));
> +	if (ret)
> +		goto exit_cdev;
> +
> +	tz->cdevs[tz->cdev_indx++] = cdev;
> +
> +exit_cdev:
> +	mutex_unlock(&cdev_list_lock);
> +exit_zone:
> +	mutex_unlock(&zone_list_lock);
> +	return ret;
> +}
> +EXPORT_SYMBOL(add_cdev_to_zone);
> +
>   /**
>    * thermal_sensor_register - register a new thermal sensor
>    * @name:	name of the thermal sensor
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index 2194519..c841414 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -57,6 +57,8 @@
>
>   #define MAX_SENSORS_PER_ZONE		5
>
> +#define MAX_CDEVS_PER_ZONE		5
> +
>   struct thermal_sensor;
>   struct thermal_zone_device;
>   struct thermal_cooling_device;
> @@ -217,6 +219,10 @@ struct thermal_zone {
>   	/* Sensor level information */
>   	int sensor_indx; /* index into 'sensors' array */
>   	struct thermal_sensor *sensors[MAX_SENSORS_PER_ZONE];
> +
> +	/* cdev level information */
> +	int cdev_indx; /* index into 'cdevs' array */
> +	struct thermal_cooling_device *cdevs[MAX_CDEVS_PER_ZONE];
>   };
>
>   /* Structure that holds thermal governor information */
> @@ -296,6 +302,9 @@ void remove_thermal_zone(struct thermal_zone *);
>   int add_sensor_to_zone(struct thermal_zone *, struct thermal_sensor *);
>   struct thermal_sensor *get_sensor_by_name(const char *);
>
> +int add_cdev_to_zone(struct thermal_zone *, struct thermal_cooling_device *);
> +struct thermal_cooling_device *get_cdev_by_name(const char *);
> +
>   #ifdef CONFIG_NET
>   extern int thermal_generate_netlink_event(struct thermal_zone_device *tz,
>   						enum events event);
>