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authorKrzysztof Kozlowski <k.kozlowski@samsung.com>2015-06-08 10:09:48 +0900
committerSebastian Reichel <sre@kernel.org>2015-06-10 16:10:59 +0200
commit5c6e3a97e969e978368df83239583771c936efea (patch)
tree53578900b4a342b85b32e889504b7160c5ab7c1e
parentfb323eccbcaff06c1ed21ab989198eb40df6e846 (diff)
power_supply: sysfs: Bring back write to writeable properties
The fix for NULL pointer exception related to calling uevent for not finished probe caused to set all writeable properties as non-writeable. This was caused by checking if property is writeable before the initial increase of power supply usage counter and in the same time using wrapper over property_is_writeable(). The wrapper returns ENODEV if the usage counter is still 0. The call trace looked like: device probe: power_supply_register() use_cnt = 0; device_add() create sysfs entries power_supply_attr_is_visible() power_supply_property_is_writeable() if (use_cnt == 0) return -ENODEV; use_cnt++; Replace the usage of wrapper with direct call to property_is_writeable() from driver. This should be safe call during device probe because implementations of this callback just return 0/1 for different properties and they do not access any of the driver's internal data. Fixes: 8e59c7f23410 ("power_supply: Fix NULL pointer dereference during bq27x00_battery probe") Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Sebastian Reichel <sre@kernel.org>
-rw-r--r--drivers/power/power_supply_sysfs.c2
-rw-r--r--include/linux/power_supply.h5
2 files changed, 6 insertions, 1 deletions
diff --git a/drivers/power/power_supply_sysfs.c b/drivers/power/power_supply_sysfs.c
index af026806cba5..ed2d7fd0c734 100644
--- a/drivers/power/power_supply_sysfs.c
+++ b/drivers/power/power_supply_sysfs.c
@@ -223,7 +223,7 @@ static umode_t power_supply_attr_is_visible(struct kobject *kobj,
if (property == attrno) {
if (psy->desc->property_is_writeable &&
- power_supply_property_is_writeable(psy, property) > 0)
+ psy->desc->property_is_writeable(psy, property) > 0)
mode |= S_IWUSR;
return mode;
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index a80f1fd01ddb..0395bcb18ddb 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -206,6 +206,11 @@ struct power_supply_desc {
int (*set_property)(struct power_supply *psy,
enum power_supply_property psp,
const union power_supply_propval *val);
+ /*
+ * property_is_writeable() will be called during registration
+ * of power supply. If this happens during device probe then it must
+ * not access internal data of device (because probe did not end).
+ */
int (*property_is_writeable)(struct power_supply *psy,
enum power_supply_property psp);
void (*external_power_changed)(struct power_supply *psy);