score: Avoid Giant lock for scheduler set/get

Update #2555.

1 files changed, 28 insertions, 22 deletions

diff --git a/cpukit/rtems/src/tasksetscheduler.c b/cpukit/rtems/src/tasksetscheduler.c
index e05553046d..428ef3dd9d 100644
--- a/cpukit/rtems/src/tasksetscheduler.c
+++ b/cpukit/rtems/src/tasksetscheduler.c
@@ -24,34 +24,40 @@ rtems_status_code rtems_task_set_scheduler(
   rtems_id scheduler_id
 )
 {
-  rtems_status_code        sc;
   const Scheduler_Control *scheduler;
+  Thread_Control          *the_thread;
+  ISR_lock_Context         lock_context;
+  ISR_lock_Context         state_lock_context;
+  Per_CPU_Control         *cpu_self;
+  void                    *lock;
+  bool                     ok;
 
-  if ( _Scheduler_Get_by_id( scheduler_id, &scheduler ) ) {
-    Thread_Control    *the_thread;
-    Objects_Locations  location;
+  if ( !_Scheduler_Get_by_id( scheduler_id, &scheduler ) ) {
+    return RTEMS_INVALID_ID;
+  }
 
-    the_thread = _Thread_Get( task_id, &location );
+  the_thread = _Thread_Get_interrupt_disable( task_id, &lock_context );
 
-    switch ( location ) {
-      case OBJECTS_LOCAL:
-        _Scheduler_Set( scheduler, the_thread );
-        _Objects_Put( &the_thread->Object );
-        sc = RTEMS_SUCCESSFUL;
-        break;
+  if ( the_thread == NULL ) {
 #if defined(RTEMS_MULTIPROCESSING)
-      case OBJECTS_REMOTE:
-        _Thread_Dispatch();
-        sc = RTEMS_ILLEGAL_ON_REMOTE_OBJECT;
-        break;
-#endif
-      default:
-        sc = RTEMS_INVALID_ID;
-        break;
+    if ( _Thread_MP_Is_remote( task_id ) ) {
+      return RTEMS_ILLEGAL_ON_REMOTE_OBJECT;
     }
-  } else {
-    sc = RTEMS_INVALID_ID;
+#endif
+
+    return RTEMS_INVALID_ID;
   }
 
-  return sc;
+  cpu_self = _Thread_Dispatch_disable_critical( &lock_context );
+  _ISR_lock_ISR_enable( &lock_context );
+
+  lock = _Thread_Lock_acquire( the_thread, &lock_context );
+  _Thread_State_acquire_critical( the_thread, &state_lock_context );
+
+  ok = _Scheduler_Set( scheduler, the_thread );
+
+  _Thread_State_release_critical( the_thread, &state_lock_context );
+  _Thread_Lock_release( lock, &lock_context );
+  _Thread_Dispatch_enable( cpu_self );
+  return ok ? RTEMS_SUCCESSFUL : RTEMS_INCORRECT_STATE;
 }