Merge branch 'akpm' (patches from Andrew Morton)

[cascardo/linux.git] / include / linux / rbtree.h

diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index aa870a4..57e75ae 100644 (file)
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -85,6 +85,11 @@ static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
        *rb_link = node;
 }
 
+#define rb_entry_safe(ptr, type, member) \
+       ({ typeof(ptr) ____ptr = (ptr); \
+          ____ptr ? rb_entry(____ptr, type, member) : NULL; \
+       })
+
 /**
  * rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of
  * given type safe against removal of rb_node entry
@@ -95,12 +100,9 @@ static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
  * @field:     the name of the rb_node field within 'type'.
  */
 #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
-       for (pos = rb_entry(rb_first_postorder(root), typeof(*pos), field),\
-               n = rb_entry(rb_next_postorder(&pos->field), \
-                       typeof(*pos), field); \
-            &pos->field; \
-            pos = n, \
-               n = rb_entry(rb_next_postorder(&pos->field), \
-                       typeof(*pos), field))
+       for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
+            pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
+                       typeof(*pos), field); 1; }); \
+            pos = n)
 
 #endif /* _LINUX_RBTREE_H */