[PATCH 6.11 regression fix] power: supply: sysfs: Revert use power_supply_property_is_writeable()

Hans de Goede
2024-09-08T14:44:28Z

power_supply_property_is_writeable() contains the following check:

if (atomic_read(&psy->use_cnt) <= 0 ||
!psy->desc->property_is_writeable)
return -ENODEV;

psy->use_cnt gets initialized to 0 and is incremented by
__power_supply_register() after it calls device_add(); and thus after
the driver core calls power_supply_attr_is_visible() to get the attr's
permissions.

So when power_supply_attr_is_visible() runs psy->use_cnt is 0 failing
the above check. This is causing all the attributes to have permissions
of 444 even those which should be writable.

Move back to manually calling psy->desc->property_is_writeable() without
the psy->use_cnt check to fix this.

Fixes: be6299c6e55e ("power: supply: sysfs: use power_supply_property_is_writeable()")
Cc: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Note this is a straight-forward revert of be6299c6e55e
---
drivers/power/supply/power_supply_sysfs.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c
index 6cd3fac1891b..fb9b67b5a9aa 100644
--- a/drivers/power/supply/power_supply_sysfs.c
+++ b/drivers/power/supply/power_supply_sysfs.c
@@ -387,7 +387,8 @@ static umode_t power_supply_attr_is_visible(struct kobject *kobj,
int property = psy->desc->properties[i];

if (property == attrno) {
- if (power_supply_property_is_writeable(psy, property) > 0)
+ if (psy->desc->property_is_writeable &&
+ psy->desc->property_is_writeable(psy, property) > 0)
mode |= S_IWUSR;

return mode;
--
2.46.0