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: 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>
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@ -336,6 +336,17 @@ static int power_supply_match_device_by_name(struct device *dev, const void *dat
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return strcmp(psy->desc->name, name) == 0;
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}
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/**
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* power_supply_get_by_name() - Search for a power supply and returns its ref
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* @name: Power supply name to fetch
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*
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* If power supply was found, it increases reference count for the
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* internal power supply's device. The user should power_supply_put()
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* after usage.
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*
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* Return: On success returns a reference to a power supply with
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* matching name equals to @name, a NULL otherwise.
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*/
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struct power_supply *power_supply_get_by_name(const char *name)
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{
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struct device *dev = class_find_device(power_supply_class, NULL, name,
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@ -345,12 +356,39 @@ struct power_supply *power_supply_get_by_name(const char *name)
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}
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EXPORT_SYMBOL_GPL(power_supply_get_by_name);
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/**
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* power_supply_put() - Drop reference obtained with power_supply_get_by_name
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* @psy: Reference to put
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*
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* The reference to power supply should be put before unregistering
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* the power supply.
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*/
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void power_supply_put(struct power_supply *psy)
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{
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might_sleep();
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put_device(&psy->dev);
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}
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EXPORT_SYMBOL_GPL(power_supply_put);
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#ifdef CONFIG_OF
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static int power_supply_match_device_node(struct device *dev, const void *data)
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{
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return dev->parent && dev->parent->of_node == data;
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}
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/**
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* power_supply_get_by_phandle() - Search for a power supply and returns its ref
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* @np: Pointer to device node holding phandle property
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* @phandle_name: Name of property holding a power supply name
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*
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* If power supply was found, it increases reference count for the
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* internal power supply's device. The user should power_supply_put()
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* after usage.
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*
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* Return: On success returns a reference to a power supply with
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* matching name equals to value under @property, NULL or ERR_PTR otherwise.
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*/
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struct power_supply *power_supply_get_by_phandle(struct device_node *np,
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const char *property)
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{
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@ -282,6 +282,7 @@ extern struct atomic_notifier_head power_supply_notifier;
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extern int power_supply_reg_notifier(struct notifier_block *nb);
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extern void power_supply_unreg_notifier(struct notifier_block *nb);
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extern struct power_supply *power_supply_get_by_name(const char *name);
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extern void power_supply_put(struct power_supply *psy);
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#ifdef CONFIG_OF
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extern struct power_supply *power_supply_get_by_phandle(struct device_node *np,
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const char *property);
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