1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _LINUX_MBCACHE_H 3#define _LINUX_MBCACHE_H 4 5#include <linux/hash.h> 6#include <linux/list_bl.h> 7#include <linux/list.h> 8#include <linux/atomic.h> 9#include <linux/fs.h> 10 11struct mb_cache; 12 13/* Cache entry flags */ 14enum { 15 MBE_REFERENCED_B = 0, 16 MBE_REUSABLE_B 17}; 18 19struct mb_cache_entry { 20 /* List of entries in cache - protected by cache->c_list_lock */ 21 struct list_head e_list; 22 /* 23 * Hash table list - protected by hash chain bitlock. The entry is 24 * guaranteed to be hashed while e_refcnt > 0. 25 */ 26 struct hlist_bl_node e_hash_list; 27 /* 28 * Entry refcount. Once it reaches zero, entry is unhashed and freed. 29 * While refcount > 0, the entry is guaranteed to stay in the hash and 30 * e.g. mb_cache_entry_try_delete() will fail. 31 */ 32 atomic_t e_refcnt; 33 /* Key in hash - stable during lifetime of the entry */ 34 u32 e_key; 35 unsigned long e_flags; 36 /* User provided value - stable during lifetime of the entry */ 37 u64 e_value; 38}; 39 40struct mb_cache *mb_cache_create(int bucket_bits); 41void mb_cache_destroy(struct mb_cache *cache); 42 43int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key, 44 u64 value, bool reusable); 45void __mb_cache_entry_free(struct mb_cache *cache, 46 struct mb_cache_entry *entry); 47void mb_cache_entry_wait_unused(struct mb_cache_entry *entry); 48static inline void mb_cache_entry_put(struct mb_cache *cache, 49 struct mb_cache_entry *entry) 50{ 51 unsigned int cnt = atomic_dec_return(&entry->e_refcnt); 52 53 if (cnt > 0) { 54 if (cnt <= 2) 55 wake_up_var(&entry->e_refcnt); 56 return; 57 } 58 __mb_cache_entry_free(cache, entry); 59} 60 61struct mb_cache_entry *mb_cache_entry_delete_or_get(struct mb_cache *cache, 62 u32 key, u64 value); 63struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key, 64 u64 value); 65struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache, 66 u32 key); 67struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache, 68 struct mb_cache_entry *entry); 69void mb_cache_entry_touch(struct mb_cache *cache, 70 struct mb_cache_entry *entry); 71 72#endif /* _LINUX_MBCACHE_H */ 73