[PATCH v3 06/11] power: supply: max17042: avoid overflow when determining health

[André Draszik]

If vmax has the default value of INT_MAX (e.g. because not specified in
DT), battery health is reported as over-voltage. This is because adding
any value to vmax (the vmax tolerance in this case) causes it to wrap
around, making it negative and smaller than the measured battery
voltage.

Avoid that by using size_add().

Fixes: edd4ab055931 ("power: max17042_battery: add HEALTH and TEMP_* properties support")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: André Draszik <andre.draszik@xxxxxxxxxx>
---
v3:
- drop a useless comment introduced in earlier versions.
---
 drivers/power/supply/max17042_battery.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/power/supply/max17042_battery.c b/drivers/power/supply/max17042_battery.c
index b9277f81a25d..39091fb31711 100644
--- a/drivers/power/supply/max17042_battery.c
+++ b/drivers/power/supply/max17042_battery.c
@@ -201,7 +201,7 @@ static int max17042_get_battery_health(struct max17042_chip *chip, int *health)
 		goto out;
 	}
 
-	if (vbatt > chip->pdata->vmax + MAX17042_VMAX_TOLERANCE) {
+	if (vbatt > size_add(chip->pdata->vmax, MAX17042_VMAX_TOLERANCE)) {
 		*health = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
 		goto out;
 	}

-- 
2.53.0.473.g4a7958ca14-goog