score: Fix blocking message queue receive

In order to ensure FIFO fairness across schedulers, the thread queue
surrender operation must be used to dequeue a thread from the thread
queue.  The thread queue extract operation is intended for timeouts.

Add _Thread_queue_Resume() which may be used to make extracted or
surrendered threads ready again.

Remove the now unused _Thread_queue_Extract_critical() function.

Close #4509.

2 files changed, 37 insertions, 28 deletions

diff --git a/cpukit/score/src/coremsgseize.c b/cpukit/score/src/coremsgseize.c
index e44538ee17..148e9dbb3c 100644
--- a/cpukit/score/src/coremsgseize.c
+++ b/cpukit/score/src/coremsgseize.c
@@ -56,7 +56,8 @@ Status_Control _CORE_message_queue_Seize(
       return STATUS_SUCCESSFUL;
     #else
     {
-      Thread_Control   *the_thread;
+      Thread_queue_Heads *heads;
+      Thread_Control     *the_thread;
 
       /*
        *  There could be a thread waiting to send a message.  If there
@@ -65,11 +66,8 @@ Status_Control _CORE_message_queue_Seize(
        *  NOTE: If we note that the queue was not full before this receive,
        *  then we can avoid this dequeue.
        */
-      the_thread = _Thread_queue_First_locked(
-        &the_message_queue->Wait_queue,
-        the_message_queue->operations
-      );
-      if ( the_thread == NULL ) {
+      heads = the_message_queue->Wait_queue.Queue.heads;
+      if ( heads == NULL ) {
         _CORE_message_queue_Free_message_buffer(
           the_message_queue,
           the_message
@@ -78,6 +76,13 @@ Status_Control _CORE_message_queue_Seize(
         return STATUS_SUCCESSFUL;
       }
 
+      the_thread = ( *the_message_queue->operations->surrender )(
+        &the_message_queue->Wait_queue.Queue,
+        heads,
+        NULL,
+        queue_context
+      );
+
       /*
        *  There was a thread waiting to send a message.  This code
        *  puts the messages in the message queue on behalf of the
@@ -90,9 +95,8 @@ Status_Control _CORE_message_queue_Seize(
         (size_t) the_thread->Wait.option,
         (CORE_message_queue_Submit_types) the_thread->Wait.count
       );
-      _Thread_queue_Extract_critical(
+      _Thread_queue_Resume(
         &the_message_queue->Wait_queue.Queue,
-        the_message_queue->operations,
         the_thread,
         queue_context
       );
diff --git a/cpukit/score/src/threadqenqueue.c b/cpukit/score/src/threadqenqueue.c
index d165e30da7..833d37ee61 100644
--- a/cpukit/score/src/threadqenqueue.c
+++ b/cpukit/score/src/threadqenqueue.c
@@ -7,9 +7,10 @@
  *   _Thread_queue_Deadlock_fatal(), _Thread_queue_Deadlock_status(),
  *   _Thread_queue_Do_dequeue(), _Thread_queue_Enqueue(),
  *   _Thread_queue_Enqueue_do_nothing_extra(), _Thread_queue_Enqueue_sticky(),
- *   _Thread_queue_Extract(), _Thread_queue_Extract_critical(),
- *   _Thread_queue_Extract_locked(), _Thread_queue_Path_acquire_critical(),
- *   _Thread_queue_Path_release_critical(), _Thread_queue_Surrender(),
+ *   _Thread_queue_Extract(), _Thread_queue_Extract_locked(),
+ *   _Thread_queue_Path_acquire_critical(),
+ *   _Thread_queue_Path_release_critical(),
+ *   _Thread_queue_Resume(),_Thread_queue_Surrender(),
  *   _Thread_queue_Surrender_sticky(), and _Thread_queue_Unblock_critical().
  */
 
@@ -604,28 +605,32 @@ void _Thread_queue_Unblock_critical(
   }
 }
 
-void _Thread_queue_Extract_critical(
-  Thread_queue_Queue            *queue,
-  const Thread_queue_Operations *operations,
-  Thread_Control                *the_thread,
-  Thread_queue_Context          *queue_context
+void _Thread_queue_Resume(
+  Thread_queue_Queue   *queue,
+  Thread_Control       *the_thread,
+  Thread_queue_Context *queue_context
 )
 {
   bool unblock;
 
-  unblock = _Thread_queue_Extract_locked(
-    queue,
-    operations,
-    the_thread,
-    queue_context
-  );
+  unblock = _Thread_queue_Make_ready_again( the_thread );
 
-  _Thread_queue_Unblock_critical(
-    unblock,
-    queue,
-    the_thread,
-    &queue_context->Lock_context.Lock_context
-  );
+  if ( unblock ) {
+    Per_CPU_Control *cpu_self;
+
+    cpu_self = _Thread_queue_Dispatch_disable( queue_context );
+    _Thread_queue_Queue_release(
+      queue, &queue_context->Lock_context.Lock_context
+    );
+
+    _Thread_Remove_timer_and_unblock( the_thread, queue );
+
+    _Thread_Dispatch_enable( cpu_self );
+  } else {
+    _Thread_queue_Queue_release(
+      queue, &queue_context->Lock_context.Lock_context
+    );
+  }
 }
 
 void _Thread_queue_Extract( Thread_Control *the_thread )