radix-tree: fix preload vector size

 */

static struct kmem_cache *radix_tree_node_cachep;

/*

 * The radix tree is variable-height, so an insert operation not only has

 * to build the branch to its corresponding item, it also has to build the

 * branch to existing items if the size has to be increased (by

 * radix_tree_extend).

 *

 * The worst case is a zero height tree with just a single item at index 0,

 * and then inserting an item at index ULONG_MAX. This requires 2 new branches

 * of RADIX_TREE_MAX_PATH size to be created, with only the root node shared.

 * Hence:

 */

#define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1)

/*

 * Per-cpu pool of preloaded nodes

 */

struct radix_tree_preload {

	int nr;

	struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH];

	struct radix_tree_node *nodes[RADIX_TREE_PRELOAD_SIZE];

};

static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };