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authorKrzysztof Kozlowski <k.kozlowski@samsung.com>2015-03-12 10:44:12 +0300
committerSebastian Reichel <sre@kernel.org>2015-03-14 01:15:52 +0300
commit1a352462b5377ac68f5955d674b3460c7bac52a3 (patch)
treeb2dbecd8b038ccaddd262af47efa4fdf64c75696 /drivers/power
parent297d716f6260cc9421d971b124ca196b957ee458 (diff)
downloadlinux-1a352462b5377ac68f5955d674b3460c7bac52a3.tar.xz
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>
Diffstat (limited to 'drivers/power')
-rw-r--r--drivers/power/power_supply_core.c38
1 files changed, 38 insertions, 0 deletions
diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index e51405b176c8..b4ec14683b7f 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -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)
{