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-rw-r--r--include/linux/rbtree.h22
1 files changed, 22 insertions, 0 deletions
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index 0022c1bb1e26..aa870a4ddf54 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -68,6 +68,10 @@ extern struct rb_node *rb_prev(const struct rb_node *);
extern struct rb_node *rb_first(const struct rb_root *);
extern struct rb_node *rb_last(const struct rb_root *);
+/* Postorder iteration - always visit the parent after its children */
+extern struct rb_node *rb_first_postorder(const struct rb_root *);
+extern struct rb_node *rb_next_postorder(const struct rb_node *);
+
/* Fast replacement of a single node without remove/rebalance/add/rebalance */
extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
struct rb_root *root);
@@ -81,4 +85,22 @@ static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
*rb_link = node;
}
+/**
+ * rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of
+ * given type safe against removal of rb_node entry
+ *
+ * @pos: the 'type *' to use as a loop cursor.
+ * @n: another 'type *' to use as temporary storage
+ * @root: 'rb_root *' of the rbtree.
+ * @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))
+
#endif /* _LINUX_RBTREE_H */