linux-stable/lib/radix-tree.h

// SPDX-License-Identifier: GPL-2.0+
/* radix-tree helpers that are only shared with xarray */

struct kmem_cache;
struct rcu_head;

extern struct kmem_cache *radix_tree_node_cachep;
extern void radix_tree_node_rcu_free(struct rcu_head *head);