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Diffstat (limited to 'include/linux/mbcache.h')
-rw-r--r--include/linux/mbcache.h33
1 files changed, 24 insertions, 9 deletions
diff --git a/include/linux/mbcache.h b/include/linux/mbcache.h
index 20f1e3ff6013..2da63fd7b98f 100644
--- a/include/linux/mbcache.h
+++ b/include/linux/mbcache.h
@@ -13,8 +13,16 @@ struct mb_cache;
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;
@@ -29,17 +37,24 @@ 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);
}
-void mb_cache_entry_delete(struct mb_cache *cache, u32 key, u64 value);
+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,