[PATCH v4 13/20] power_supply: Increment power supply use counter when obtaining references
From: Krzysztof Kozlowski <hidden>
Date: 2015-02-23 11:48:31
Also in:
linux-acpi, linux-arm-kernel, linux-input, linux-tegra, lkml, platform-driver-x86
Subsystem:
the rest · Maintainer:
Linus Torvalds
Increment the power_supply.use_cnt usage counter on: - power_supply_get_by_phandle() - power_supply_get_by_name() and decrement it on power_supply_put() call. This helps tracking of valid usage of power supply instance by consumers. The usage counter itself also allows safe calling of power_supply_get_property-like functions even when driver unregisters this power supply. Signed-off-by: Krzysztof Kozlowski <redacted> Reviewed-by: Bartlomiej Zolnierkiewicz <redacted> --- drivers/power/power_supply_core.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index a94f8c9d5e1e..819430a0bfa6 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c@@ -349,10 +349,16 @@ static int power_supply_match_device_by_name(struct device *dev, const void *dat */ struct power_supply *power_supply_get_by_name(const char *name) { + struct power_supply *psy = NULL; struct device *dev = class_find_device(power_supply_class, NULL, name, power_supply_match_device_by_name); - return dev ? dev_get_drvdata(dev) : NULL; + if (dev) { + psy = dev_get_drvdata(dev); + atomic_inc(&psy->use_cnt); + } + + return psy; } EXPORT_SYMBOL_GPL(power_supply_get_by_name);
@@ -367,6 +373,7 @@ void power_supply_put(struct power_supply *psy) { might_sleep(); + atomic_dec(&psy->use_cnt); put_device(&psy->dev); } EXPORT_SYMBOL_GPL(power_supply_put);
@@ -393,6 +400,7 @@ struct power_supply *power_supply_get_by_phandle(struct device_node *np, const char *property) { struct device_node *power_supply_np; + struct power_supply *psy = NULL; struct device *dev; power_supply_np = of_parse_phandle(np, property, 0);
@@ -404,7 +412,12 @@ struct power_supply *power_supply_get_by_phandle(struct device_node *np, of_node_put(power_supply_np); - return dev ? dev_get_drvdata(dev) : NULL; + if (dev) { + psy = dev_get_drvdata(dev); + atomic_inc(&psy->use_cnt); + } + + return psy; } EXPORT_SYMBOL_GPL(power_supply_get_by_phandle); #endif /* CONFIG_OF */
--
1.9.1