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