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