RADIX_TREE_MAX_HEIGHT
#define RADIX_TREE_INVALID_HEIGHT (RADIX_TREE_MAX_HEIGHT + 1)
} p_refs[RADIX_TREE_MAX_HEIGHT + 1]; /* +1 for the root ptr */
struct radix_tree_node *nodes[RADIX_TREE_MAX_HEIGHT];
struct radix_tree_node *newnodes[RADIX_TREE_MAX_HEIGHT];
KASSERT(newheight <= RADIX_TREE_MAX_HEIGHT);