[rtems commit] Fix rbtree_postorder_for_each_entry_safe()

[Sebastian Huber]

Module:    rtems
Branch:    master
Commit:    4a7c68675d26990b6d28b9820b837322e2b234a2
Changeset: http://git.rtems.org/rtems/commit/?id=4a7c68675d26990b6d28b9820b837322e2b234a2

Author:    Sebastian Huber <sebastian.huber at embedded-brains.de>
Date:      Fri Oct  5 09:37:44 2018 +0200

Fix rbtree_postorder_for_each_entry_safe()

Use the non-standard typeof operator to avoid code generation errors
with clang and use of uninitialized variable warnings with GCC and
Coverity Scan.

Update #3465.

---

 cpukit/include/linux/rbtree.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/cpukit/include/linux/rbtree.h b/cpukit/include/linux/rbtree.h
index 53c777e..8fc5752 100644
--- a/cpukit/include/linux/rbtree.h
+++ b/cpukit/include/linux/rbtree.h
@@ -126,12 +126,12 @@ static inline struct rb_node *rb_parent( struct rb_node *node )
   for ( \
     node = _RBTree_Postorder_first( \
       (RBTree_Control *) root, \
-      (size_t) ( (char *) &node->field - (char *) node ) \
+      offsetof( __typeof__( *node ), field ) \
     ); \
     node != NULL && ( \
       next = _RBTree_Postorder_next( \
         &node->field, \
-        (size_t) ( (char *) &node->field - (char *) node ) \
+        offsetof( __typeof__( *node ), field ) \
       ), \
       node != NULL \
     ); \