#ifndef IOU_ALLOC_CACHE_H#define IOU_ALLOC_CACHE_H /* * Don't allow the cache to grow beyond this size. */#define IO_ALLOC_CACHE_MAX	512 struct io_cache_entry {	struct hlist_node	node;}; static inline bool io_alloc_cache_put(struct io_alloc_cache *cache,				      struct io_cache_entry *entry){	if (cache->nr_cached < IO_ALLOC_CACHE_MAX) {		cache->nr_cached++;		hlist_add_head(&entry->node, &cache->list);		return true;	}	return false;} static inline struct io_cache_entry *io_alloc_cache_get(struct io_alloc_cache *cache){	if (!hlist_empty(&cache->list)) {		struct hlist_node *node = cache->list.first; 		hlist_del(node);		cache->nr_cached--;		return container_of(node, struct io_cache_entry, node);	} 	return NULL;} static inline void io_alloc_cache_init(struct io_alloc_cache *cache){	INIT_HLIST_HEAD(&cache->list);	cache->nr_cached = 0;} static inline void io_alloc_cache_free(struct io_alloc_cache *cache,					void (*free)(struct io_cache_entry *)){	while (!hlist_empty(&cache->list)) {		struct hlist_node *node = cache->list.first; 		hlist_del(node);		free(container_of(node, struct io_cache_entry, node));	}	cache->nr_cached = 0;}#endif