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power_supply: Add power_supply_put for decrementing device reference counter

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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: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
This commit is contained in:
Krzysztof Kozlowski 2015-03-12 08:44:12 +01:00 committed by Sebastian Reichel
parent 297d716f62
commit 1a352462b5
2 changed files with 39 additions and 0 deletions
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38
drivers/power/power_supply_core.c
View file

@ -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)
{

1
include/linux/power_supply.h
View file

@ -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);