1 files changed, 62 insertions, 43 deletions

diff --git a/include/linux/mbcache.h b/include/linux/mbcache.h
index 5525d370701d..97e64184767d 100644
--- a/include/linux/mbcache.h
+++ b/include/linux/mbcache.h
@@ -1,53 +1,72 @@
-/*
-  File: linux/mbcache.h
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MBCACHE_H
+#define _LINUX_MBCACHE_H
 
-  (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
-*/
+#include <linux/hash.h>
+#include <linux/list_bl.h>
+#include <linux/list.h>
+#include <linux/atomic.h>
+#include <linux/fs.h>
 
-struct mb_cache_entry {
-	struct list_head		e_lru_list;
-	struct mb_cache			*e_cache;
-	unsigned short			e_used;
-	unsigned short			e_queued;
-	struct block_device		*e_bdev;
-	sector_t			e_block;
-	struct list_head		e_block_list;
-	struct {
-		struct list_head	o_list;
-		unsigned int		o_key;
-	} e_index;
+struct mb_cache;
+
+/* Cache entry flags */
+enum {
+	MBE_REFERENCED_B = 0,
+	MBE_REUSABLE_B
 };
 
-struct mb_cache {
-	struct list_head		c_cache_list;
-	const char			*c_name;
-	atomic_t			c_entry_count;
-	int				c_max_entries;
-	int				c_bucket_bits;
-	struct kmem_cache		*c_entry_cache;
-	struct list_head		*c_block_hash;
-	struct list_head		*c_index_hash;
+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;
 };
 
-/* Functions on caches */
+struct mb_cache *mb_cache_create(int bucket_bits);
+void mb_cache_destroy(struct mb_cache *cache);
 
-struct mb_cache *mb_cache_create(const char *, int);
-void mb_cache_shrink(struct block_device *);
-void mb_cache_destroy(struct mb_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);
 
-/* Functions on cache entries */
+	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_alloc(struct mb_cache *, gfp_t);
-int mb_cache_entry_insert(struct mb_cache_entry *, struct block_device *,
-			  sector_t, unsigned int);
-void mb_cache_entry_release(struct mb_cache_entry *);
-void mb_cache_entry_free(struct mb_cache_entry *);
-struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *,
-					  struct block_device *,
-					  sector_t);
+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,
-						 struct block_device *, 
-						 unsigned int);
-struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache_entry *,
-						struct block_device *, 
-						unsigned int);
+						 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 */