score: Avoid Giant lock for CBS scheduler

Update #2555.

1 files changed, 20 insertions, 17 deletions

diff --git a/cpukit/score/src/schedulercbsgetexecutiontime.c b/cpukit/score/src/schedulercbsgetexecutiontime.c
index ee139e640d..a16d297b48 100644
--- a/cpukit/score/src/schedulercbsgetexecutiontime.c
+++ b/cpukit/score/src/schedulercbsgetexecutiontime.c
@@ -28,30 +28,33 @@ int _Scheduler_CBS_Get_execution_time (
   time_t                   *abs_time
 )
 {
-  Objects_Locations location;
-  Thread_Control *the_thread;
+  Scheduler_CBS_Server *server;
+  ISR_lock_Context      lock_context;
+  Thread_Control       *the_thread;
 
-  if ( server_id >= _Scheduler_CBS_Maximum_servers )
+  if ( server_id >= _Scheduler_CBS_Maximum_servers ) {
     return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
-  if ( !_Scheduler_CBS_Server_list[server_id].initialized )
+  }
+
+  server = &_Scheduler_CBS_Server_list[ server_id ];
+
+  if ( !server->initialized ) {
     return SCHEDULER_CBS_ERROR_NOSERVER;
-  if ( _Scheduler_CBS_Server_list[server_id].task_id == -1 ) {
+  }
+
+  if ( server->task_id == -1 ) {
     *exec_time = 0;
     return SCHEDULER_CBS_OK;
   }
 
-  the_thread = _Thread_Get(
-                 _Scheduler_CBS_Server_list[server_id].task_id,
-                 &location
-               );
-  /* The routine _Thread_Get may disable dispatch and not enable again. */
-  if ( the_thread ) {
-    *exec_time = _Scheduler_CBS_Server_list[server_id].parameters.budget -
-      the_thread->cpu_time_budget;
-    _Objects_Put( &the_thread->Object );
-  }
-  else {
-    *exec_time = _Scheduler_CBS_Server_list[server_id].parameters.budget;
+  the_thread = _Thread_Get_interrupt_disable( server->task_id, &lock_context );
+
+  if ( the_thread != NULL ) {
+    *exec_time = server->parameters.budget - the_thread->cpu_time_budget;
+    _ISR_lock_ISR_enable( &lock_context );
+  } else {
+    *exec_time = server->parameters.budget;
   }
+
   return SCHEDULER_CBS_OK;
 }