diff options
| -rw-r--r-- | include/linux/rbtree.h | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h index 830c4992088d..a5aa7ae671f4 100644 --- a/include/linux/rbtree.h +++ b/include/linux/rbtree.h @@ -101,13 +101,21 @@ static inline void rb_link_node_rcu(struct rb_node *node, struct rb_node *parent }) /** - * rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of - * given type safe against removal of rb_node entry + * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of + * given type allowing the backing memory of @pos to be invalidated * * @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'. + * + * rbtree_postorder_for_each_entry_safe() provides a similar guarantee as + * list_for_each_entry_safe() and allows the iteration to continue independent + * of changes to @pos by the body of the loop. + * + * Note, however, that it cannot handle other modifications that re-order the + * rbtree it is iterating over. This includes calling rb_erase() on @pos, as + * rb_erase() may rebalance the tree, causing us to miss some nodes. */ #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \ for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \ |