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power: supply: core: Add power_supply_get/set_property_direct()

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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 <hansg@kernel.org>
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Hans de Goede <hansg@kernel.org>
Link: https://lore.kernel.org/r/20250627205124.250433-1-W_Armin@gmx.de
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
This commit is contained in:
Armin Wolf
2025-06-27 22:51:22 +02:00
committed by Ilpo Järvinen
parent 8346c6af27
commit 3ebed2fddf
2 changed files with 78 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

82
drivers/power/supply/power_supply_core.c
View File

@@ -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)
{

8
include/linux/power_supply.h
View File

@@ -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);