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