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 | /* Cache entry flags */ |
14 | enum { |
15 | MBE_REFERENCED_B = 0, |
16 | MBE_REUSABLE_B |
17 | }; |
18 | |
19 | struct 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 | |
40 | struct mb_cache *mb_cache_create(int bucket_bits); |
41 | void mb_cache_destroy(struct mb_cache *cache); |
42 | |
43 | int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key, |
44 | u64 value, bool reusable); |
45 | void __mb_cache_entry_free(struct mb_cache *cache, |
46 | struct mb_cache_entry *entry); |
47 | void mb_cache_entry_wait_unused(struct mb_cache_entry *entry); |
48 | static inline void mb_cache_entry_put(struct mb_cache *cache, |
49 | struct mb_cache_entry *entry) |
50 | { |
51 | unsigned int cnt = atomic_dec_return(v: &entry->e_refcnt); |
52 | |
53 | if (cnt > 0) { |
54 | if (cnt <= 2) |
55 | wake_up_var(var: &entry->e_refcnt); |
56 | return; |
57 | } |
58 | __mb_cache_entry_free(cache, entry); |
59 | } |
60 | |
61 | struct mb_cache_entry *mb_cache_entry_delete_or_get(struct mb_cache *cache, |
62 | u32 key, u64 value); |
63 | struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key, |
64 | u64 value); |
65 | struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache, |
66 | u32 key); |
67 | struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache, |
68 | struct mb_cache_entry *entry); |
69 | void mb_cache_entry_touch(struct mb_cache *cache, |
70 | struct mb_cache_entry *entry); |
71 | |
72 | #endif /* _LINUX_MBCACHE_H */ |
73 | |