exec_list: Fix foreach_list_safe.

It now works correctly when nodes are removed, as it was originally
intended to do; it no longer processes nodes added to the list before
the current node, nor those added immediately after the current node.

This matches the behavior of Linux's list_for_each_safe.

1 files changed, 5 insertions, 11 deletions

diff --git a/src/glsl/list.h b/src/glsl/list.h
index 29997c78ee8..7348e323c1b 100644
--- a/src/glsl/list.h
+++ b/src/glsl/list.h
@@ -433,18 +433,12 @@ struct exec_list {
 };
 
 /**
- * This version is safe even if the current node is removed.  If you insert
- * new nodes before the current node, they will be processed next.
- *
- * \note
- * The extra test for \c __node being \c NULL is required because after the
- * iteration \c __prev coupld be the last node in the list.  The loop increment
- * then causes \c __prev to point to the sentinal and \c __node to be \c NULL.
+ * This version is safe even if the current node is removed.
  */ 
-#define foreach_list_safe(__node, __list)		\
-   for (exec_node * __prev = (exec_node *) (__list), * __node = (__list)->head \
-        ; __node != NULL && (__node)->next != NULL	\
-	; __prev = (__prev)->next, __node = (__prev)->next)
+#define foreach_list_safe(__node, __list)			     \
+   for (exec_node * __node = (__list)->head, * __next = __node->next \
+	; __next != NULL					     \
+	; __node = __next, __next = __next->next)
 
 #define foreach_list(__node, __list)			\
    for (exec_node * __node = (__list)->head		\