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// 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.
*/
void btrfs_lru_cache_init(struct btrfs_lru_cache *cache, unsigned int max_size)
{
INIT_LIST_HEAD(&cache->lru_list);
mt_init(&cache->entries);
cache->size = 0;
cache->max_size = max_size;
}
/*
* Lookup for an entry in the cache.
*
* @cache: The cache.
* @key: The key of the entry we are looking for.
*
* 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)
{
struct btrfs_lru_cache_entry *entry;
entry = mtree_load(&cache->entries, key);
if (entry)
list_move_tail(&entry->lru_list, &cache->lru_list);
return 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)
{
int ret;
if (cache->size == cache->max_size) {
struct btrfs_lru_cache_entry *lru_entry;
struct btrfs_lru_cache_entry *mt_entry;
lru_entry = list_first_entry(&cache->lru_list,
struct btrfs_lru_cache_entry,
lru_list);
mt_entry = mtree_erase(&cache->entries, lru_entry->key);
ASSERT(mt_entry == lru_entry);
list_del(&mt_entry->lru_list);
kfree(mt_entry);
cache->size--;
}
ret = mtree_insert(&cache->entries, new_entry->key, new_entry, gfp);
if (ret < 0)
return ret;
list_add_tail(&new_entry->lru_list, &cache->lru_list);
cache->size++;
return 0;
}
/*
* Empty a cache.
*
* @cache: The cache to empty.
*
* Removes all entries from the cache.
*/
void btrfs_lru_cache_clear(struct btrfs_lru_cache *cache)
{
struct btrfs_lru_cache_entry *entry;
struct btrfs_lru_cache_entry *tmp;
list_for_each_entry_safe(entry, tmp, &cache->lru_list, lru_list)
kfree(entry);
INIT_LIST_HEAD(&cache->lru_list);
mtree_destroy(&cache->entries);
cache->size = 0;
}
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