[PATCH v1 1/6] thermal: trip: Simplify computing trip indices

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

A trip index can be computed right away as a difference between the
value of a trip pointer pointing to the given trip object and the
start of the trips[] table in the thermal zone containing the trip, so
change thermal_zone_trip_id() accordingly.

No intentional functional impact (except for some speedup).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
 drivers/thermal/thermal_trip.c |   13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

Index: linux-pm/drivers/thermal/thermal_trip.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_trip.c
+++ linux-pm/drivers/thermal/thermal_trip.c
@@ -175,14 +175,11 @@ int thermal_zone_set_trip(struct thermal
 int thermal_zone_trip_id(struct thermal_zone_device *tz,
 			 const struct thermal_trip *trip)
 {
-	int i;
-
 	lockdep_assert_held(&tz->lock);
 
-	for (i = 0; i < tz->num_trips; i++) {
-		if (&tz->trips[i] == trip)
-			return i;
-	}
-
-	return -ENODATA;
+	/*
+	 * Assume the trip to be located within the bounds of the thermal
+	 * zone's trips[] table.
+	 */
+	return trip - tz->trips;
 }