[PATCH v1 1/4] hwmon: (acpi_power_meter) Fix using uninitialized variables

[Huisong Li <lihuisong@huawei.com>]

The 'power1_alarm' attribute uses the 'power' and 'cap' in the
acpi_power_meter_resource structure. However, these two fields are just
updated when user query 'power' and 'cap' attribute, or hardware enforced
limit. If user directly query the 'power1_alarm' attribute without queryng
above two attributes, driver will use the uninitialized variables to judge.
In addition, the 'power1_alarm' attribute needs to update power and cap to
show the real state.

Signed-off-by: Huisong Li <lihuisong@huawei.com>
---
 drivers/hwmon/acpi_power_meter.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/hwmon/acpi_power_meter.c b/drivers/hwmon/acpi_power_meter.c
index 2f1c9d97ad21..4c3314e35d30 100644
--- a/drivers/hwmon/acpi_power_meter.c
+++ b/drivers/hwmon/acpi_power_meter.c
@@ -396,6 +396,9 @@ static ssize_t show_val(struct device *dev,
 	struct acpi_device *acpi_dev = to_acpi_device(dev);
 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 	u64 val = 0;
+	int ret;
+
+	guard(mutex)(&resource->lock);
 
 	switch (attr->index) {
 	case 0:
@@ -423,6 +426,13 @@ static ssize_t show_val(struct device *dev,
 			val = 0;
 		break;
 	case 6:
+		ret = update_meter(resource);
+		if (ret)
+			return ret;
+		ret = update_cap(resource);
+		if (ret)
+			return ret;
+
 		if (resource->power > resource->cap)
 			val = 1;
 		else
-- 
2.22.0