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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_MBCACHE_H
#define _LINUX_MBCACHE_H
#include <linux/hash.h>
#include <linux/list_bl.h>
#include <linux/list.h>
#include <linux/atomic.h>
#include <linux/fs.h>
struct mb_cache;
/* Cache entry flags */
enum {
MBE_REFERENCED_B = 0,
MBE_REUSABLE_B
};
struct mb_cache_entry {
/* List of entries in cache - protected by cache->c_list_lock */
struct list_head e_list;
/*
* Hash table list - protected by hash chain bitlock. The entry is
* guaranteed to be hashed while e_refcnt > 0.
*/
struct hlist_bl_node e_hash_list;
/*
* Entry refcount. Once it reaches zero, entry is unhashed and freed.
* While refcount > 0, the entry is guaranteed to stay in the hash and
* e.g. mb_cache_entry_try_delete() will fail.
*/
atomic_t e_refcnt;
/* Key in hash - stable during lifetime of the entry */
u32 e_key;
unsigned long e_flags;
/* User provided value - stable during lifetime of the entry */
u64 e_value;
};
struct mb_cache *mb_cache_create(int bucket_bits);
void mb_cache_destroy(struct mb_cache *cache);
int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
u64 value, bool reusable);
void __mb_cache_entry_free(struct mb_cache *cache,
struct mb_cache_entry *entry);
void mb_cache_entry_wait_unused(struct mb_cache_entry *entry);
static inline void mb_cache_entry_put(struct mb_cache *cache,
struct mb_cache_entry *entry)
{
unsigned int cnt = atomic_dec_return(&entry->e_refcnt);
if (cnt > 0) {
if (cnt <= 2)
wake_up_var(&entry->e_refcnt);
return;
}
__mb_cache_entry_free(cache, entry);
}
struct mb_cache_entry *mb_cache_entry_delete_or_get(struct mb_cache *cache,
u32 key, u64 value);
struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
u64 value);
struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache,
u32 key);
struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache,
struct mb_cache_entry *entry);
void mb_cache_entry_touch(struct mb_cache *cache,
struct mb_cache_entry *entry);
#endif /* _LINUX_MBCACHE_H */
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