diff options
Diffstat (limited to 'include/linux/mbcache.h')
-rw-r--r-- | include/linux/mbcache.h | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/include/linux/mbcache.h b/include/linux/mbcache.h new file mode 100644 index 000000000..97e641847 --- /dev/null +++ b/include/linux/mbcache.h @@ -0,0 +1,72 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_MBCACHE_H +#define _LINUX_MBCACHE_H + +#include <linux/hash.h> +#include <linux/list_bl.h> +#include <linux/list.h> +#include <linux/atomic.h> +#include <linux/fs.h> + +struct mb_cache; + +/* Cache entry flags */ +enum { + MBE_REFERENCED_B = 0, + MBE_REUSABLE_B +}; + +struct mb_cache_entry { + /* List of entries in cache - protected by cache->c_list_lock */ + struct list_head e_list; + /* + * Hash table list - protected by hash chain bitlock. The entry is + * guaranteed to be hashed while e_refcnt > 0. + */ + struct hlist_bl_node e_hash_list; + /* + * Entry refcount. Once it reaches zero, entry is unhashed and freed. + * While refcount > 0, the entry is guaranteed to stay in the hash and + * e.g. mb_cache_entry_try_delete() will fail. + */ + atomic_t e_refcnt; + /* Key in hash - stable during lifetime of the entry */ + u32 e_key; + unsigned long e_flags; + /* User provided value - stable during lifetime of the entry */ + u64 e_value; +}; + +struct mb_cache *mb_cache_create(int bucket_bits); +void mb_cache_destroy(struct mb_cache *cache); + +int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key, + u64 value, bool reusable); +void __mb_cache_entry_free(struct mb_cache *cache, + struct mb_cache_entry *entry); +void mb_cache_entry_wait_unused(struct mb_cache_entry *entry); +static inline void mb_cache_entry_put(struct mb_cache *cache, + struct mb_cache_entry *entry) +{ + unsigned int cnt = atomic_dec_return(&entry->e_refcnt); + + if (cnt > 0) { + if (cnt <= 2) + wake_up_var(&entry->e_refcnt); + return; + } + __mb_cache_entry_free(cache, entry); +} + +struct mb_cache_entry *mb_cache_entry_delete_or_get(struct mb_cache *cache, + u32 key, u64 value); +struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key, + u64 value); +struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache, + u32 key); +struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache, + struct mb_cache_entry *entry); +void mb_cache_entry_touch(struct mb_cache *cache, + struct mb_cache_entry *entry); + +#endif /* _LINUX_MBCACHE_H */ |