score: Rework _Thread_Change_priority()

Move the writes to Thread_Control::current_priority and
Thread_Control::real_priority into _Thread_Change_priority() under the
protection of the thread lock.  Add a filter function to
_Thread_Change_priority() to enable specialized variants.

Avoid race conditions during a thread priority restore with the new
Thread_Control::priority_restore_hint for an important average case
optimizations used by priority inheritance mutexes.

Update #2273.

1 files changed, 11 insertions, 9 deletions

diff --git a/cpukit/rtems/src/tasksetpriority.c b/cpukit/rtems/src/tasksetpriority.c
index 4e4835675d..582c67f9f2 100644
--- a/cpukit/rtems/src/tasksetpriority.c
+++ b/cpukit/rtems/src/tasksetpriority.c
@@ -41,16 +41,18 @@ rtems_status_code rtems_task_set_priority(
   switch ( location ) {
 
     case OBJECTS_LOCAL:
-      *old_priority = _RTEMS_tasks_Priority_from_Core(
-                        the_thread->current_priority
-                      );
       if ( new_priority != RTEMS_CURRENT_PRIORITY ) {
-        the_thread->real_priority = _RTEMS_tasks_Priority_to_Core(
-                                      new_priority
-                                    );
-        if ( !_Thread_Owns_resources( the_thread ) ||
-             the_thread->current_priority > new_priority )
-          _Thread_Change_priority( the_thread, new_priority, false );
+        _Thread_Set_priority(
+          the_thread,
+          _RTEMS_tasks_Priority_to_Core( new_priority ),
+          old_priority,
+          false
+        );
+        *old_priority = _RTEMS_tasks_Priority_from_Core( *old_priority );
+      } else {
+        *old_priority = _RTEMS_tasks_Priority_from_Core(
+          the_thread->current_priority
+        );
       }
       _Objects_Put( &the_thread->Object );
       return RTEMS_SUCCESSFUL;