From: Armin Wolf Date: Fri, 27 Jun 2025 20:51:22 +0000 (+0200) Subject: power: supply: core: Add power_supply_get/set_property_direct() X-Git-Tag: v6.16~19^2~13 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3ebed2fddf6fac5729ffc8c471c87d111b641678;p=thirdparty%2Flinux.git power: supply: core: Add power_supply_get/set_property_direct() Power supply extensions might want to interact with the underlying power supply to retrieve data like serial numbers, charging status and more. However doing so causes psy->extensions_sem to be locked twice, possibly causing a deadlock. Provide special variants of power_supply_get/set_property() that ignore any power supply extensions and thus do not touch the associated psy->extensions_sem lock. Suggested-by: Hans de Goede Signed-off-by: Armin Wolf Acked-by: Sebastian Reichel Reviewed-by: Hans de Goede Link: https://lore.kernel.org/r/20250627205124.250433-1-W_Armin@gmx.de Reviewed-by: Ilpo Järvinen Signed-off-by: Ilpo Järvinen --- diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c index 33a5bfce4604f..cfb0e3e0d4aa0 100644 --- a/drivers/power/supply/power_supply_core.c +++ b/drivers/power/supply/power_supply_core.c @@ -1235,9 +1235,8 @@ bool power_supply_has_property(struct power_supply *psy, return false; } -int power_supply_get_property(struct power_supply *psy, - enum power_supply_property psp, - union power_supply_propval *val) +static int __power_supply_get_property(struct power_supply *psy, enum power_supply_property psp, + union power_supply_propval *val, bool use_extensions) { struct power_supply_ext_registration *reg; @@ -1247,10 +1246,14 @@ int power_supply_get_property(struct power_supply *psy, return -ENODEV; } - scoped_guard(rwsem_read, &psy->extensions_sem) { - power_supply_for_each_extension(reg, psy) { - if (power_supply_ext_has_property(reg->ext, psp)) + if (use_extensions) { + scoped_guard(rwsem_read, &psy->extensions_sem) { + power_supply_for_each_extension(reg, psy) { + if (!power_supply_ext_has_property(reg->ext, psp)) + continue; + return reg->ext->get_property(psy, reg->ext, reg->data, psp, val); + } } } @@ -1261,20 +1264,49 @@ int power_supply_get_property(struct power_supply *psy, else return -EINVAL; } + +int power_supply_get_property(struct power_supply *psy, enum power_supply_property psp, + union power_supply_propval *val) +{ + return __power_supply_get_property(psy, psp, val, true); +} EXPORT_SYMBOL_GPL(power_supply_get_property); -int power_supply_set_property(struct power_supply *psy, - enum power_supply_property psp, - const union power_supply_propval *val) +/** + * power_supply_get_property_direct - Read a power supply property without checking for extensions + * @psy: The power supply + * @psp: The power supply property to read + * @val: The resulting value of the power supply property + * + * Read a power supply property without taking into account any power supply extensions registered + * on the given power supply. This is mostly useful for power supply extensions that want to access + * their own power supply as using power_supply_get_property() directly will result in a potential + * deadlock. + * + * Return: 0 on success or negative error code on failure. + */ +int power_supply_get_property_direct(struct power_supply *psy, enum power_supply_property psp, + union power_supply_propval *val) +{ + return __power_supply_get_property(psy, psp, val, false); +} +EXPORT_SYMBOL_GPL(power_supply_get_property_direct); + + +static int __power_supply_set_property(struct power_supply *psy, enum power_supply_property psp, + const union power_supply_propval *val, bool use_extensions) { struct power_supply_ext_registration *reg; if (atomic_read(&psy->use_cnt) <= 0) return -ENODEV; - scoped_guard(rwsem_read, &psy->extensions_sem) { - power_supply_for_each_extension(reg, psy) { - if (power_supply_ext_has_property(reg->ext, psp)) { + if (use_extensions) { + scoped_guard(rwsem_read, &psy->extensions_sem) { + power_supply_for_each_extension(reg, psy) { + if (!power_supply_ext_has_property(reg->ext, psp)) + continue; + if (reg->ext->set_property) return reg->ext->set_property(psy, reg->ext, reg->data, psp, val); @@ -1289,8 +1321,34 @@ int power_supply_set_property(struct power_supply *psy, return psy->desc->set_property(psy, psp, val); } + +int power_supply_set_property(struct power_supply *psy, enum power_supply_property psp, + const union power_supply_propval *val) +{ + return __power_supply_set_property(psy, psp, val, true); +} EXPORT_SYMBOL_GPL(power_supply_set_property); +/** + * power_supply_set_property_direct - Write a power supply property without checking for extensions + * @psy: The power supply + * @psp: The power supply property to write + * @val: The value to write to the power supply property + * + * Write a power supply property without taking into account any power supply extensions registered + * on the given power supply. This is mostly useful for power supply extensions that want to access + * their own power supply as using power_supply_set_property() directly will result in a potential + * deadlock. + * + * Return: 0 on success or negative error code on failure. + */ +int power_supply_set_property_direct(struct power_supply *psy, enum power_supply_property psp, + const union power_supply_propval *val) +{ + return __power_supply_set_property(psy, psp, val, false); +} +EXPORT_SYMBOL_GPL(power_supply_set_property_direct); + int power_supply_property_is_writeable(struct power_supply *psy, enum power_supply_property psp) { diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h index 7803edaa8ff8d..0cca01b5607b1 100644 --- a/include/linux/power_supply.h +++ b/include/linux/power_supply.h @@ -888,15 +888,23 @@ static inline int power_supply_is_system_supplied(void) { return -ENOSYS; } extern int power_supply_get_property(struct power_supply *psy, enum power_supply_property psp, union power_supply_propval *val); +int power_supply_get_property_direct(struct power_supply *psy, enum power_supply_property psp, + union power_supply_propval *val); #if IS_ENABLED(CONFIG_POWER_SUPPLY) extern int power_supply_set_property(struct power_supply *psy, enum power_supply_property psp, const union power_supply_propval *val); +int power_supply_set_property_direct(struct power_supply *psy, enum power_supply_property psp, + const union power_supply_propval *val); #else static inline int power_supply_set_property(struct power_supply *psy, enum power_supply_property psp, const union power_supply_propval *val) { return 0; } +static inline int power_supply_set_property_direct(struct power_supply *psy, + enum power_supply_property psp, + const union power_supply_propval *val) +{ return 0; } #endif extern void power_supply_external_power_changed(struct power_supply *psy);