linux/fs/btrfs/lru_cache.c

// SPDX-License-Identifier: GPL-2.0

#include <linux/mm.h>
#include "lru_cache.h"
#include "messages.h"

/*
 * Initialize a cache object.
 *
 * @cache:      The cache.
 * @max_size:   Maximum size (number of entries) for the cache.
 *              Use 0 for unlimited size, it's the user's responsibility to
 *              trim the cache in that case.
 */
void btrfs_lru_cache_init(struct btrfs_lru_cache *cache, unsigned int max_size)
{ … }

static struct btrfs_lru_cache_entry *match_entry(struct list_head *head, u64 key,
						 u64 gen)
{ … }

/*
 * Lookup for an entry in the cache.
 *
 * @cache:      The cache.
 * @key:        The key of the entry we are looking for.
 * @gen:        Generation associated to the key.
 *
 * Returns the entry associated with the key or NULL if none found.
 */
struct btrfs_lru_cache_entry *btrfs_lru_cache_lookup(struct btrfs_lru_cache *cache,
						     u64 key, u64 gen)
{ … }

/*
 * Remove an entry from the cache.
 *
 * @cache:     The cache to remove from.
 * @entry:     The entry to remove from the cache.
 *
 * Note: this also frees the memory used by the entry.
 */
void btrfs_lru_cache_remove(struct btrfs_lru_cache *cache,
			    struct btrfs_lru_cache_entry *entry)
{ … }

/*
 * Store an entry in the cache.
 *
 * @cache:      The cache.
 * @entry:      The entry to store.
 *
 * Returns 0 on success and < 0 on error.
 */
int btrfs_lru_cache_store(struct btrfs_lru_cache *cache,
			  struct btrfs_lru_cache_entry *new_entry,
			  gfp_t gfp)
{ … }

/*
 * Empty a cache.
 *
 * @cache:     The cache to empty.
 *
 * Removes all entries from the cache.
 */
void btrfs_lru_cache_clear(struct btrfs_lru_cache *cache)
{ … }