thermal: ACPI: Discard trips table after zone registration

Because the thermal core creates and uses its own copy of the trips
table passed to thermal_zone_device_register_with_trips(), it is not
necessary to hold on to a local copy of it any more after the given
thermal zone has been registered.

Accordingly, modify the ACPI thermal driver to store the trips table
passed to thermal_zone_device_register_with_trips() in a local variable
which is automatically discarded when acpi_thermal_add() returns to
its caller.

Also make some additional code simplifications unlocked by the above
change.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>

diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
index 4748e8061253444cd84634c19042b72fcdc3e39b..6c4ba00d60e2138e54cd59c15c4bf6a7f597851d 100644 (file)
--- a/drivers/acpi/thermal.c
+++ b/drivers/acpi/thermal.c
@@ -47,6 +47,8 @@
 
 #define ACPI_THERMAL_TRIP_PASSIVE      (-1)
 
+#define ACPI_THERMAL_MAX_NR_TRIPS      (ACPI_THERMAL_MAX_ACTIVE + 3)
+
 /*
  * This exception is thrown out in two cases:
  * 1.An invalid trip point becomes invalid or a valid trip point becomes invalid
@@ -112,7 +114,6 @@ struct acpi_thermal {
        unsigned long polling_frequency;
        volatile u8 zombie;
        struct acpi_thermal_trips trips;
-       struct thermal_trip *trip_table;
        struct thermal_zone_device *thermal_zone;
        int kelvin_offset;      /* in millidegrees */
        struct work_struct thermal_check_work;
@@ -451,26 +452,19 @@ fail:
        return false;
 }
 
-static int acpi_thermal_get_trip_points(struct acpi_thermal *tz)
+static void acpi_thermal_get_trip_points(struct acpi_thermal *tz)
 {
-       unsigned int count = 0;
        int i;
 
-       if (acpi_thermal_init_trip(tz, ACPI_THERMAL_TRIP_PASSIVE))
-               count++;
+       acpi_thermal_init_trip(tz, ACPI_THERMAL_TRIP_PASSIVE);
 
        for (i = 0; i < ACPI_THERMAL_MAX_ACTIVE; i++) {
-               if (acpi_thermal_init_trip(tz, i))
-                       count++;
-               else
+               if (!acpi_thermal_init_trip(tz, i))
                        break;
-
        }
 
        while (++i < ACPI_THERMAL_MAX_ACTIVE)
                tz->trips.active[i].trip.temp_dk = THERMAL_TEMP_INVALID;
-
-       return count;
 }
 
 /* sys I/F for generic thermal sysfs support */
@@ -662,13 +656,14 @@ static void acpi_thermal_zone_sysfs_remove(struct acpi_thermal *tz)
 }
 
 static int acpi_thermal_register_thermal_zone(struct acpi_thermal *tz,
+                                             const struct thermal_trip *trip_table,
                                              unsigned int trip_count,
                                              int passive_delay)
 {
        int result;
 
        tz->thermal_zone = thermal_zone_device_register_with_trips("acpitz",
-                                                                  tz->trip_table,
+                                                                  trip_table,
                                                                   trip_count,
                                                                   0, tz,
                                                                   &acpi_thermal_zone_ops,
@@ -823,10 +818,10 @@ static void acpi_thermal_free_thermal_zone(struct acpi_thermal *tz)
 
 static int acpi_thermal_add(struct acpi_device *device)
 {
+       struct thermal_trip trip_table[ACPI_THERMAL_MAX_NR_TRIPS] = { 0 };
        struct acpi_thermal_trip *acpi_trip;
        struct thermal_trip *trip;
        struct acpi_thermal *tz;
-       unsigned int trip_count;
        int crit_temp, hot_temp;
        int passive_delay = 0;
        int result;
@@ -848,21 +843,10 @@ static int acpi_thermal_add(struct acpi_device *device)
        acpi_thermal_aml_dependency_fix(tz);
 
        /* Get trip points [_CRT, _PSV, etc.] (required). */
-       trip_count = acpi_thermal_get_trip_points(tz);
+       acpi_thermal_get_trip_points(tz);
 
        crit_temp = acpi_thermal_get_critical_trip(tz);
-       if (crit_temp != THERMAL_TEMP_INVALID)
-               trip_count++;
-
        hot_temp = acpi_thermal_get_hot_trip(tz);
-       if (hot_temp != THERMAL_TEMP_INVALID)
-               trip_count++;
-
-       if (!trip_count) {
-               pr_warn(FW_BUG "No valid trip points!\n");
-               result = -ENODEV;
-               goto free_memory;
-       }
 
        /* Get temperature [_TMP] (required). */
        result = acpi_thermal_get_temperature(tz);
@@ -881,13 +865,7 @@ static int acpi_thermal_add(struct acpi_device *device)
 
        acpi_thermal_guess_offset(tz, crit_temp);
 
-       trip = kcalloc(trip_count, sizeof(*trip), GFP_KERNEL);
-       if (!trip) {
-               result = -ENOMEM;
-               goto free_memory;
-       }
-
-       tz->trip_table = trip;
+       trip = trip_table;
 
        if (crit_temp != THERMAL_TEMP_INVALID) {
                trip->type = THERMAL_TRIP_CRITICAL;
@@ -923,9 +901,17 @@ static int acpi_thermal_add(struct acpi_device *device)
                trip++;
        }
 
-       result = acpi_thermal_register_thermal_zone(tz, trip_count, passive_delay);
+       if (trip == trip_table) {
+               pr_warn(FW_BUG "No valid trip points!\n");
+               result = -ENODEV;
+               goto free_memory;
+       }
+
+       result = acpi_thermal_register_thermal_zone(tz, trip_table,
+                                                   trip - trip_table,
+                                                   passive_delay);
        if (result)
-               goto free_trips;
+               goto free_memory;
 
        refcount_set(&tz->thermal_check_count, 3);
        mutex_init(&tz->thermal_check_lock);
@@ -944,8 +930,6 @@ static int acpi_thermal_add(struct acpi_device *device)
 flush_wq:
        flush_workqueue(acpi_thermal_pm_queue);
        acpi_thermal_unregister_thermal_zone(tz);
-free_trips:
-       kfree(tz->trip_table);
 free_memory:
        acpi_thermal_free_thermal_zone(tz);
 
@@ -966,7 +950,6 @@ static void acpi_thermal_remove(struct acpi_device *device)
 
        flush_workqueue(acpi_thermal_pm_queue);
        acpi_thermal_unregister_thermal_zone(tz);
-       kfree(tz->trip_table);
        acpi_thermal_free_thermal_zone(tz);
 }