Re: 2.6.24-rc1: OOPS at acpi_battery_update

[Alexey Starikovskiy]

Rafael J. Wysocki wrote:
> On Thursday, 8 of November 2007, Johannes Weiner wrote:
> > Hi,
> >
> > is there any reason, why acpi_battery_get_property() should call
> > acpi_battery_update() at all?
>
> Alex?
Do you mean "why should it call _whole_ battery update?" ?
get_state should be sufficient in order to not get stale data.

Regards,
Alex.
ACPI: Battery: remove cycle from battery removal.

From: Alexey Starikovskiy <astarikovskiy@xxxxxxx>

get_property() should not call battery_update() on absent battery to
avoid cycle and oops.

Signed-off-by: Alexey Starikovskiy <astarikovskiy@xxxxxxx>
Tested-by: Rolf Eike Beer <eike-kernel@xxxxxxxxx>
---

 drivers/acpi/battery.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index c2ce0ad..192c244 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -132,7 +132,7 @@ static int acpi_battery_technology(struct acpi_battery *battery)
 	return POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
 }
 
-static int acpi_battery_update(struct acpi_battery *battery);
+static int acpi_battery_get_state(struct acpi_battery *battery);
 
 static int acpi_battery_get_property(struct power_supply *psy,
 				     enum power_supply_property psp,
@@ -140,10 +140,11 @@ static int acpi_battery_get_property(struct power_supply *psy,
 {
 	struct acpi_battery *battery = to_acpi_battery(psy);
 
-	if ((!acpi_battery_present(battery)) &&
-	     psp != POWER_SUPPLY_PROP_PRESENT)
+	if (acpi_battery_present(battery)) {
+		/* run battery update only if it is present */
+		acpi_battery_get_state(battery);
+	} else if (psp != POWER_SUPPLY_PROP_PRESENT)
 		return -ENODEV;
-	acpi_battery_update(battery);
 	switch (psp) {
 	case POWER_SUPPLY_PROP_STATUS:
 		if (battery->state & 0x01)
@@ -457,6 +458,7 @@ static void sysfs_remove_battery(struct acpi_battery *battery)
 		return;
 	device_remove_file(battery->bat.dev, &alarm_attr);
 	power_supply_unregister(&battery->bat);
+	battery->bat.dev = NULL;
 }
 
 static int acpi_battery_update(struct acpi_battery *battery)