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

["R, Durgadoss" <durgadoss.r@intel.com>]

> -----Original Message-----
> From: Eduardo Valentin [mailto:eduardo.valentin@ti.com]
> Sent: Friday, March 01, 2013 1:06 AM
> To: R, Durgadoss
> Cc: Zhang, Rui; linux-pm@vger.kernel.org; linux-kernel@vger.kernel.org;
> hongbo.zhang@linaro.org; wni@nvidia.com
> Subject: Re: [PATCH 3/8] Thermal: Add APIs to bind cdev to new zone
> structure
> 
> 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?

Yes, as I said in 02/08.

> - get_by_name, why do we need it? (at least not on this patch)

The platform drivers need this API to query the pointer for cdevs,
sensors.

Thanks,
Durga

> - 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);
> >