[PATCH v4 2/6] thermal: core: Free thermal zone ID later during removal

[Rafael J. Wysocki]

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

The thermal zone removal ordering is different from the thermal zone
registration rollback path ordering and the former is arguably
problematic because freeing a thermal zone ID prematurely may cause
it to be used during the registration of another thermal zone which
may fail as a result.

Prevent that from occurring by changing the thermal zone removal
ordering to reflect the thermal zone registration rollback path
ordering.

Also more the ida_destroy() call from thermal_zone_device_unregister()
to thermal_release() for consistency.

Fixes: b31ef8285b19 ("thermal core: convert ID allocation to IDA")
Cc: All applicable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---

v3 -> v4:
   * Call ida_destroy() in thermal_release() in analogy with the mutex
     cleanup

v2 -> v3: New patch

---
 drivers/thermal/thermal_core.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -972,6 +972,7 @@ static void thermal_release(struct devic
 		tz = to_thermal_zone(dev);
 		thermal_zone_destroy_device_groups(tz);
 		thermal_set_governor(tz, NULL);
+		ida_destroy(&tz->ida);
 		mutex_destroy(&tz->lock);
 		complete(&tz->removal);
 	} else if (!strncmp(dev_name(dev), "cooling_device",
@@ -1736,8 +1737,6 @@ void thermal_zone_device_unregister(stru
 
 	thermal_thresholds_exit(tz);
 	thermal_remove_hwmon_sysfs(tz);
-	ida_free(&thermal_tz_ida, tz->id);
-	ida_destroy(&tz->ida);
 
 	device_del(&tz->device);
 	put_device(&tz->device);
@@ -1745,6 +1744,9 @@ void thermal_zone_device_unregister(stru
 	thermal_notify_tz_delete(tz);
 
 	wait_for_completion(&tz->removal);
+
+	ida_free(&thermal_tz_ida, tz->id);
+
 	kfree(tz->tzp);
 	kfree(tz);
 }