Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 1a352462 authored by Krzysztof Kozlowski's avatar Krzysztof Kozlowski Committed by Sebastian Reichel
Browse files

power_supply: Add power_supply_put for decrementing device reference counter 



The power_supply_get_by_phandle() and power_supply_get_by_name() use
function class_find_device() for obtaining the reference to power
supply. Each use of class_find_device() increases the power supply's
device reference counter.

However the reference counter was not decreased by users of this API.
Thus final device_unregister() call from power_supply_unregister() could
not release the device and clean up its resources. This lead to memory
leak if at least once power_supply_get_by_*() was called between
registering and unregistering the power supply.

Add and document new API power_supply_put() for decrementing the
reference counter.

Signed-off-by: default avatarKrzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Reviewed-by: default avatarBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: default avatarSebastian Reichel <sre@kernel.org>
Signed-off-by: default avatarSebastian Reichel <sre@kernel.org>
parent 297d716f

drivers/power/power_supply_core.c

+38 −0
Original line number Diff line number Diff line
@@ -336,6 +336,17 @@ static int power_supply_match_device_by_name(struct device *dev, const void *dat 
	return strcmp(psy->desc->name, name) == 0;

}



/**

 * power_supply_get_by_name() - Search for a power supply and returns its ref

 * @name: Power supply name to fetch

 *

 * If power supply was found, it increases reference count for the

 * internal power supply's device. The user should power_supply_put()

 * after usage.

 *

 * Return: On success returns a reference to a power supply with

 * matching name equals to @name, a NULL otherwise.

 */

struct power_supply *power_supply_get_by_name(const char *name)

{

	struct device *dev = class_find_device(power_supply_class, NULL, name,
@@ -345,12 +356,39 @@ struct power_supply *power_supply_get_by_name(const char *name) 
}

EXPORT_SYMBOL_GPL(power_supply_get_by_name);



/**

 * power_supply_put() - Drop reference obtained with power_supply_get_by_name

 * @psy: Reference to put

 *

 * The reference to power supply should be put before unregistering

 * the power supply.

 */

void power_supply_put(struct power_supply *psy)

{

	might_sleep();



	put_device(&psy->dev);

}

EXPORT_SYMBOL_GPL(power_supply_put);



#ifdef CONFIG_OF

static int power_supply_match_device_node(struct device *dev, const void *data)

{

	return dev->parent && dev->parent->of_node == data;

}



/**

 * power_supply_get_by_phandle() - Search for a power supply and returns its ref

 * @np: Pointer to device node holding phandle property

 * @phandle_name: Name of property holding a power supply name

 *

 * If power supply was found, it increases reference count for the

 * internal power supply's device. The user should power_supply_put()

 * after usage.

 *

 * Return: On success returns a reference to a power supply with

 * matching name equals to value under @property, NULL or ERR_PTR otherwise.

 */

struct power_supply *power_supply_get_by_phandle(struct device_node *np,

							const char *property)

{

include/linux/power_supply.h

+1 −0
Original line number Diff line number Diff line
@@ -282,6 +282,7 @@ extern struct atomic_notifier_head power_supply_notifier; 
extern int power_supply_reg_notifier(struct notifier_block *nb);

extern void power_supply_unreg_notifier(struct notifier_block *nb);

extern struct power_supply *power_supply_get_by_name(const char *name);

extern void power_supply_put(struct power_supply *psy);

#ifdef CONFIG_OF

extern struct power_supply *power_supply_get_by_phandle(struct device_node *np,

							const char *property);