diff options
Diffstat (limited to '')
| -rw-r--r-- | include/linux/mbcache.h | 41 |
1 files changed, 31 insertions, 10 deletions
diff --git a/include/linux/mbcache.h b/include/linux/mbcache.h index 20f1e3ff6..591bc4cef 100644 --- a/include/linux/mbcache.h +++ b/include/linux/mbcache.h @@ -10,16 +10,29 @@ 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 */ + /* + * 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; - u32 e_referenced:1; - u32 e_reusable:1; + unsigned long e_flags; /* User provided value - stable during lifetime of the entry */ u64 e_value; }; @@ -29,16 +42,24 @@ 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_entry *entry); -static inline int mb_cache_entry_put(struct mb_cache *cache, - struct mb_cache_entry *entry) +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) { - if (!atomic_dec_and_test(&entry->e_refcnt)) - return 0; - __mb_cache_entry_free(entry); - return 1; + 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); void mb_cache_entry_delete(struct mb_cache *cache, u32 key, u64 value); struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key, u64 value); |