6.10-stable review patch. If anyone has any objections, please let me know.
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From: Rafael J. Wysocki rafael.j.wysocki@intel.com
[ Upstream commit a52641bc6293a24f25956a597e7f32148b0e2bb8 ]
When accessing trip temperature and hysteresis without locking, it is better to use READ_ONCE() to prevent compiler optimizations possibly affecting the read from being applied.
Of course, for the READ_ONCE() to be effective, WRITE_ONCE() needs to be used when updating their values.
Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/thermal/thermal_sysfs.c | 6 +++--- drivers/thermal/thermal_trip.c | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c index 88211ccdfbd6..5be6113e7c80 100644 --- a/drivers/thermal/thermal_sysfs.c +++ b/drivers/thermal/thermal_sysfs.c @@ -150,7 +150,7 @@ trip_point_temp_show(struct device *dev, struct device_attribute *attr, if (sscanf(attr->attr.name, "trip_point_%d_temp", &trip_id) != 1) return -EINVAL;
- return sprintf(buf, "%d\n", tz->trips[trip_id].trip.temperature); + return sprintf(buf, "%d\n", READ_ONCE(tz->trips[trip_id].trip.temperature)); }
static ssize_t @@ -174,7 +174,7 @@ trip_point_hyst_store(struct device *dev, struct device_attribute *attr, trip = &tz->trips[trip_id].trip;
if (hyst != trip->hysteresis) { - trip->hysteresis = hyst; + WRITE_ONCE(trip->hysteresis, hyst);
thermal_zone_trip_updated(tz, trip); } @@ -194,7 +194,7 @@ trip_point_hyst_show(struct device *dev, struct device_attribute *attr, if (sscanf(attr->attr.name, "trip_point_%d_hyst", &trip_id) != 1) return -EINVAL;
- return sprintf(buf, "%d\n", tz->trips[trip_id].trip.hysteresis); + return sprintf(buf, "%d\n", READ_ONCE(tz->trips[trip_id].trip.hysteresis)); }
static ssize_t diff --git a/drivers/thermal/thermal_trip.c b/drivers/thermal/thermal_trip.c index 49e63db68517..b4e7411b2fe7 100644 --- a/drivers/thermal/thermal_trip.c +++ b/drivers/thermal/thermal_trip.c @@ -152,7 +152,7 @@ void thermal_zone_set_trip_temp(struct thermal_zone_device *tz, if (trip->temperature == temp) return;
- trip->temperature = temp; + WRITE_ONCE(trip->temperature, temp); thermal_notify_tz_trip_change(tz, trip);
if (temp == THERMAL_TEMP_INVALID) {