rbtree: Rename find header in find control

Simplify _RBTree_Find_control().  Avoid superfluous NULL pointer checks.

cpukit/sapi/include/rtems/rbtree.h

@@ -369,13 +369,13 @@ RTEMS_INLINE_ROUTINE rtems_rbtree_node *rtems_rbtree_peek_max(
 }
 
 /**
- * @copydoc _RBTree_Find_header()
+ * @copydoc _RBTree_Find_control()
  */
-RTEMS_INLINE_ROUTINE rtems_rbtree_control *rtems_rbtree_find_header(
-  rtems_rbtree_node *the_node
+RTEMS_INLINE_ROUTINE rtems_rbtree_control *rtems_rbtree_find_control(
+  const rtems_rbtree_node *the_node
 )
 {
-  return _RBTree_Find_header( the_node );
+  return _RBTree_Find_control( the_node );
 }
 
 /**

cpukit/score/include/rtems/score/rbtree.h

@@ -431,19 +431,28 @@ RTEMS_INLINE_ROUTINE bool _RBTree_Is_root(
 }
 
 /**
- * @brief Find the RBTree_Control header given a node in the tree.
+ * @brief Finds the red-black tree control given a node in the tree.
  *
- * This function returns a pointer to the header of the Red Black
- * Tree containing @a the_node if it exists, and NULL if not.
+ * In case the node is not a node of a tree, then this function yields
+ * unpredictable results.
+ *
+ * @param[in] the_node The node of interest.
+ *
+ * @return The red-black tree control of the node.
  */
-RTEMS_INLINE_ROUTINE RBTree_Control *_RBTree_Find_header(
-    RBTree_Node *the_node
-    )
+RTEMS_INLINE_ROUTINE RBTree_Control *_RBTree_Find_control(
+  const RBTree_Node *the_node
+)
 {
-  if(!the_node) return NULL;
-  if(!(the_node->parent)) return NULL;
-  while(the_node->parent) the_node = the_node->parent;
-  return (RBTree_Control*)the_node;
+  RBTree_Node    *parent = the_node->parent;
+  RBTree_Control *rbtree;
+
+  do {
+    rbtree = (RBTree_Control *) parent;
+    parent = parent->parent;
+  } while ( parent != NULL );
+
+  return rbtree;
 }
 
 /**

testsuites/sptests/sprbtree01/init.c

@@ -580,8 +580,8 @@ rtems_task Init( rtems_task_argument ignored )
   }
 
   p = rb_find_unique(&rbtree1, &search_node.Node);
-  puts( "INIT - Verify rtems_rbtree_find_header" );
-  if (rtems_rbtree_find_header(p) != &rbtree1) {
+  puts( "INIT - Verify rtems_rbtree_find_control" );
+  if (rtems_rbtree_find_control(p) != &rbtree1) {
     puts ("INIT - ERROR ON RBTREE HEADER MISMATCH");
     rtems_test_exit(0);
   }
@@ -620,11 +620,6 @@ rtems_task Init( rtems_task_argument ignored )
     rtems_test_exit(0);
   }
 
-  if (rtems_rbtree_find_header(NULL) != NULL) {
-    puts ("INIT - ERROR ON RBTREE HEADER MISMATCH");
-    rtems_test_exit(0);
-  }
-
   puts("INIT - Insert 20 random numbers");
   for (i = 0; i < 20; i++) {
     node_array[i].id = numbers[i];

testsuites/sptests/sprbtree01/sprbtree01.scn

@@ -18,7 +18,7 @@ INIT - Removing 100 nodes
 INIT - Verify rtems_rbtree_get_max with 100 nodes value [0,99]
 INIT - Verify rtems_rbtree_find
 INIT - Verify rtems_rbtree_predecessor/successor
-INIT - Verify rtems_rbtree_find_header
+INIT - Verify rtems_rbtree_find_control
 INIT - Removing 100 nodes
 INIT - Insert 20 random numbers
 INIT - Removing 20 nodes