[deliverable/linux.git] / drivers / staging / zcache / tmem.h

/*
 * tmem.h
 *
 * Transcendent memory
 *
 * Copyright (c) 2009-2011, Dan Magenheimer, Oracle Corp.
 */

#ifndef _TMEM_H_
#define _TMEM_H_

#include <linux/types.h>
#include <linux/highmem.h>
#include <linux/hash.h>
#include <linux/atomic.h>

/*
 * These are pre-defined by the Xen<->Linux ABI
 */
#define TMEM_PUT_PAGE			4
#define TMEM_GET_PAGE			5
#define TMEM_FLUSH_PAGE			6
#define TMEM_FLUSH_OBJECT		7
#define TMEM_POOL_PERSIST		1
#define TMEM_POOL_SHARED		2
#define TMEM_POOL_PRECOMPRESSED		4
#define TMEM_POOL_PAGESIZE_SHIFT	4
#define TMEM_POOL_PAGESIZE_MASK		0xf
#define TMEM_POOL_RESERVED_BITS		0x00ffff00

/*
 * sentinels have proven very useful for debugging but can be removed
 * or disabled before final merge.
 */
#define SENTINELS
#ifdef SENTINELS
#define DECL_SENTINEL uint32_t sentinel;
#define SET_SENTINEL(_x, _y) (_x->sentinel = _y##_SENTINEL)
#define INVERT_SENTINEL(_x, _y) (_x->sentinel = ~_y##_SENTINEL)
#define ASSERT_SENTINEL(_x, _y) WARN_ON(_x->sentinel != _y##_SENTINEL)
#define ASSERT_INVERTED_SENTINEL(_x, _y) WARN_ON(_x->sentinel != ~_y##_SENTINEL)
#else
#define DECL_SENTINEL
#define SET_SENTINEL(_x, _y) do { } while (0)
#define INVERT_SENTINEL(_x, _y) do { } while (0)
#define ASSERT_SENTINEL(_x, _y) do { } while (0)
#define ASSERT_INVERTED_SENTINEL(_x, _y) do { } while (0)
#endif

#define ASSERT_SPINLOCK(_l)	lockdep_assert_held(_l)

/*
 * A pool is the highest-level data structure managed by tmem and
 * usually corresponds to a large independent set of pages such as
 * a filesystem.  Each pool has an id, and certain attributes and counters.
 * It also contains a set of hash buckets, each of which contains an rbtree
 * of objects and a lock to manage concurrency within the pool.
 */

#define TMEM_HASH_BUCKET_BITS	8
#define TMEM_HASH_BUCKETS	(1<<TMEM_HASH_BUCKET_BITS)

struct tmem_hashbucket {
	struct rb_root obj_rb_root;
	spinlock_t lock;
};

struct tmem_pool {
	void *client; /* "up" for some clients, avoids table lookup */
	struct list_head pool_list;
	uint32_t pool_id;
	bool persistent;
	bool shared;
	atomic_t obj_count;
	atomic_t refcount;
	struct tmem_hashbucket hashbucket[TMEM_HASH_BUCKETS];
	DECL_SENTINEL
};

#define is_persistent(_p)  (_p->persistent)
#define is_ephemeral(_p)   (!(_p->persistent))

/*
 * An object id ("oid") is large: 192-bits (to ensure, for example, files
 * in a modern filesystem can be uniquely identified).
 */

struct tmem_oid {
	uint64_t oid[3];
};

static inline void tmem_oid_set_invalid(struct tmem_oid *oidp)
{
	oidp->oid[0] = oidp->oid[1] = oidp->oid[2] = -1UL;
}

static inline bool tmem_oid_valid(struct tmem_oid *oidp)
{
	return oidp->oid[0] != -1UL || oidp->oid[1] != -1UL ||
		oidp->oid[2] != -1UL;
}

static inline int tmem_oid_compare(struct tmem_oid *left,
					struct tmem_oid *right)
{
	int ret;

	if (left->oid[2] == right->oid[2]) {
		if (left->oid[1] == right->oid[1]) {
			if (left->oid[0] == right->oid[0])
				ret = 0;
			else if (left->oid[0] < right->oid[0])
				ret = -1;
			else
				return 1;
		} else if (left->oid[1] < right->oid[1])
			ret = -1;
		else
			ret = 1;
	} else if (left->oid[2] < right->oid[2])
		ret = -1;
	else
		ret = 1;
	return ret;
}

static inline unsigned tmem_oid_hash(struct tmem_oid *oidp)
{
	return hash_long(oidp->oid[0] ^ oidp->oid[1] ^ oidp->oid[2],
				TMEM_HASH_BUCKET_BITS);
}

/*
 * A tmem_obj contains an identifier (oid), pointers to the parent
 * pool and the rb_tree to which it belongs, counters, and an ordered
 * set of pampds, structured in a radix-tree-like tree.  The intermediate
 * nodes of the tree are called tmem_objnodes.
 */

struct tmem_objnode;

struct tmem_obj {
	struct tmem_oid oid;
	struct tmem_pool *pool;
	struct rb_node rb_tree_node;
	struct tmem_objnode *objnode_tree_root;
	unsigned int objnode_tree_height;
	unsigned long objnode_count;
	long pampd_count;
	void *extra; /* for private use by pampd implementation */
	DECL_SENTINEL
};

#define OBJNODE_TREE_MAP_SHIFT 6
#define OBJNODE_TREE_MAP_SIZE (1UL << OBJNODE_TREE_MAP_SHIFT)
#define OBJNODE_TREE_MAP_MASK (OBJNODE_TREE_MAP_SIZE-1)
#define OBJNODE_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long))
#define OBJNODE_TREE_MAX_PATH \
		(OBJNODE_TREE_INDEX_BITS/OBJNODE_TREE_MAP_SHIFT + 2)

struct tmem_objnode {
	struct tmem_obj *obj;
	DECL_SENTINEL
	void *slots[OBJNODE_TREE_MAP_SIZE];
	unsigned int slots_in_use;
};

/* pampd abstract datatype methods provided by the PAM implementation */
struct tmem_pamops {
	void *(*create)(char *, size_t, bool, int,
			struct tmem_pool *, struct tmem_oid *, uint32_t);
	int (*get_data)(char *, size_t *, bool, void *, struct tmem_pool *,
				struct tmem_oid *, uint32_t);
	int (*get_data_and_free)(char *, size_t *, bool, void *,
				struct tmem_pool *, struct tmem_oid *,
				uint32_t);
	void (*free)(void *, struct tmem_pool *, struct tmem_oid *, uint32_t);
	void (*free_obj)(struct tmem_pool *, struct tmem_obj *);
	bool (*is_remote)(void *);
	void (*new_obj)(struct tmem_obj *);
	int (*replace_in_obj)(void *, struct tmem_obj *);
};
extern void tmem_register_pamops(struct tmem_pamops *m);

/* memory allocation methods provided by the host implementation */
struct tmem_hostops {
	struct tmem_obj *(*obj_alloc)(struct tmem_pool *);
	void (*obj_free)(struct tmem_obj *, struct tmem_pool *);
	struct tmem_objnode *(*objnode_alloc)(struct tmem_pool *);
	void (*objnode_free)(struct tmem_objnode *, struct tmem_pool *);
};
extern void tmem_register_hostops(struct tmem_hostops *m);

/* core tmem accessor functions */
extern int tmem_put(struct tmem_pool *, struct tmem_oid *, uint32_t index,
			char *, size_t, bool, bool);
extern int tmem_get(struct tmem_pool *, struct tmem_oid *, uint32_t index,
			char *, size_t *, bool, int);
extern int tmem_replace(struct tmem_pool *, struct tmem_oid *, uint32_t index,
			void *);
extern int tmem_flush_page(struct tmem_pool *, struct tmem_oid *,
			uint32_t index);
extern int tmem_flush_object(struct tmem_pool *, struct tmem_oid *);
extern int tmem_destroy_pool(struct tmem_pool *);
extern void tmem_new_pool(struct tmem_pool *, uint32_t);
#endif /* _TMEM_H */
Commit	Line	Data
daa6afa6 DM	1	/*
	2	* tmem.h
	3	*
	4	* Transcendent memory
	5	*
	6	* Copyright (c) 2009-2011, Dan Magenheimer, Oracle Corp.
	7	*/
	8
	9	#ifndef _TMEM_H_
	10	#define _TMEM_H_
	11
	12	#include <linux/types.h>
	13	#include <linux/highmem.h>
	14	#include <linux/hash.h>
	15	#include <linux/atomic.h>
	16
	17	/*
	18	* These are pre-defined by the Xen<->Linux ABI
	19	*/
	20	#define TMEM_PUT_PAGE 4
	21	#define TMEM_GET_PAGE 5
	22	#define TMEM_FLUSH_PAGE 6
	23	#define TMEM_FLUSH_OBJECT 7
	24	#define TMEM_POOL_PERSIST 1
	25	#define TMEM_POOL_SHARED 2
	26	#define TMEM_POOL_PRECOMPRESSED 4
	27	#define TMEM_POOL_PAGESIZE_SHIFT 4
	28	#define TMEM_POOL_PAGESIZE_MASK 0xf
	29	#define TMEM_POOL_RESERVED_BITS 0x00ffff00
	30
	31	/*
	32	* sentinels have proven very useful for debugging but can be removed
	33	* or disabled before final merge.
	34	*/
	35	#define SENTINELS
	36	#ifdef SENTINELS
	37	#define DECL_SENTINEL uint32_t sentinel;
	38	#define SET_SENTINEL(_x, _y) (_x->sentinel = _y##_SENTINEL)
	39	#define INVERT_SENTINEL(_x, _y) (_x->sentinel = ~_y##_SENTINEL)
	40	#define ASSERT_SENTINEL(_x, _y) WARN_ON(_x->sentinel != _y##_SENTINEL)
	41	#define ASSERT_INVERTED_SENTINEL(_x, _y) WARN_ON(_x->sentinel != ~_y##_SENTINEL)
	42	#else
	43	#define DECL_SENTINEL
	44	#define SET_SENTINEL(_x, _y) do { } while (0)
	45	#define INVERT_SENTINEL(_x, _y) do { } while (0)
	46	#define ASSERT_SENTINEL(_x, _y) do { } while (0)
	47	#define ASSERT_INVERTED_SENTINEL(_x, _y) do { } while (0)
	48	#endif
	49
bc01caf5	50	#define ASSERT_SPINLOCK(_l) lockdep_assert_held(_l)
daa6afa6 DM	51
	52	/*
	53	* A pool is the highest-level data structure managed by tmem and
	54	* usually corresponds to a large independent set of pages such as
	55	* a filesystem. Each pool has an id, and certain attributes and counters.
	56	* It also contains a set of hash buckets, each of which contains an rbtree
	57	* of objects and a lock to manage concurrency within the pool.
	58	*/
	59
	60	#define TMEM_HASH_BUCKET_BITS 8
	61	#define TMEM_HASH_BUCKETS (1<<TMEM_HASH_BUCKET_BITS)
	62
	63	struct tmem_hashbucket {
	64	struct rb_root obj_rb_root;
	65	spinlock_t lock;
	66	};
	67
	68	struct tmem_pool {
	69	void client; / "up" for some clients, avoids table lookup */
	70	struct list_head pool_list;
	71	uint32_t pool_id;
	72	bool persistent;
	73	bool shared;
	74	atomic_t obj_count;
	75	atomic_t refcount;
	76	struct tmem_hashbucket hashbucket[TMEM_HASH_BUCKETS];
	77	DECL_SENTINEL
	78	};
	79
	80	#define is_persistent(_p) (_p->persistent)
	81	#define is_ephemeral(_p) (!(_p->persistent))
	82
	83	/*
	84	* An object id ("oid") is large: 192-bits (to ensure, for example, files
	85	* in a modern filesystem can be uniquely identified).
	86	*/
	87
	88	struct tmem_oid {
	89	uint64_t oid[3];
	90	};
	91
	92	static inline void tmem_oid_set_invalid(struct tmem_oid *oidp)
	93	{
	94	oidp->oid[0] = oidp->oid[1] = oidp->oid[2] = -1UL;
	95	}
	96
	97	static inline bool tmem_oid_valid(struct tmem_oid *oidp)
	98	{
	99	return oidp->oid[0] != -1UL \|\| oidp->oid[1] != -1UL \|\|
	100	oidp->oid[2] != -1UL;
	101	}
	102
	103	static inline int tmem_oid_compare(struct tmem_oid *left,
	104	struct tmem_oid *right)
	105	{
	106	int ret;
	107
	108	if (left->oid[2] == right->oid[2]) {
	109	if (left->oid[1] == right->oid[1]) {
	110	if (left->oid[0] == right->oid[0])
	111	ret = 0;
	112	else if (left->oid[0] < right->oid[0])
	113	ret = -1;
	114	else
115	return 1;
116	} else if (left->oid[1] < right->oid[1])
117	ret = -1;
118	else
119	ret = 1;
120	} else if (left->oid[2] < right->oid[2])
121	ret = -1;
122	else
123	ret = 1;
124	return ret;
125	}
126
127	static inline unsigned tmem_oid_hash(struct tmem_oid *oidp)
128	{
129	return hash_long(oidp->oid[0] ^ oidp->oid[1] ^ oidp->oid[2],
130	TMEM_HASH_BUCKET_BITS);
131	}
132
133	/*
134	* A tmem_obj contains an identifier (oid), pointers to the parent
135	* pool and the rb_tree to which it belongs, counters, and an ordered
136	* set of pampds, structured in a radix-tree-like tree. The intermediate
137	* nodes of the tree are called tmem_objnodes.
138	*/
139
140	struct tmem_objnode;
141
142	struct tmem_obj {
143	struct tmem_oid oid;
144	struct tmem_pool *pool;
145	struct rb_node rb_tree_node;
146	struct tmem_objnode *objnode_tree_root;
147	unsigned int objnode_tree_height;
148	unsigned long objnode_count;
149	long pampd_count;
966b9016	150	void extra; / for private use by pampd implementation */
daa6afa6 DM	151	DECL_SENTINEL
	152	};
	153
	154	#define OBJNODE_TREE_MAP_SHIFT 6
	155	#define OBJNODE_TREE_MAP_SIZE (1UL << OBJNODE_TREE_MAP_SHIFT)
	156	#define OBJNODE_TREE_MAP_MASK (OBJNODE_TREE_MAP_SIZE-1)
	157	#define OBJNODE_TREE_INDEX_BITS (8 /* CHAR_BIT / sizeof(unsigned long))
	158	#define OBJNODE_TREE_MAX_PATH \
	159	(OBJNODE_TREE_INDEX_BITS/OBJNODE_TREE_MAP_SHIFT + 2)
	160
	161	struct tmem_objnode {
	162	struct tmem_obj *obj;
	163	DECL_SENTINEL
	164	void *slots[OBJNODE_TREE_MAP_SIZE];
	165	unsigned int slots_in_use;
	166	};
	167
	168	/* pampd abstract datatype methods provided by the PAM implementation */
	169	struct tmem_pamops {
966b9016 DM	170	void (create)(char *, size_t, bool, int,
	171	struct tmem_pool , struct tmem_oid , uint32_t);
	172	int (get_data)(char , size_t , bool, void , struct tmem_pool *,
	173	struct tmem_oid *, uint32_t);
	174	int (get_data_and_free)(char , size_t , bool, void ,
	175	struct tmem_pool , struct tmem_oid ,
	176	uint32_t);
	177	void (free)(void , struct tmem_pool , struct tmem_oid , uint32_t);
	178	void (free_obj)(struct tmem_pool , struct tmem_obj *);
	179	bool (is_remote)(void );
	180	void (new_obj)(struct tmem_obj );
	181	int (replace_in_obj)(void , struct tmem_obj *);
daa6afa6 DM	182	};
	183	extern void tmem_register_pamops(struct tmem_pamops *m);
	184
	185	/* memory allocation methods provided by the host implementation */
	186	struct tmem_hostops {
	187	struct tmem_obj (obj_alloc)(struct tmem_pool *);
	188	void (obj_free)(struct tmem_obj , struct tmem_pool *);
	189	struct tmem_objnode (objnode_alloc)(struct tmem_pool *);
	190	void (objnode_free)(struct tmem_objnode , struct tmem_pool *);
	191	};
	192	extern void tmem_register_hostops(struct tmem_hostops *m);
	193
	194	/* core tmem accessor functions */
	195	extern int tmem_put(struct tmem_pool , struct tmem_oid , uint32_t index,
966b9016	196	char *, size_t, bool, bool);
daa6afa6	197	extern int tmem_get(struct tmem_pool , struct tmem_oid , uint32_t index,
966b9016 DM	198	char , size_t , bool, int);
	199	extern int tmem_replace(struct tmem_pool , struct tmem_oid , uint32_t index,
	200	void *);
daa6afa6 DM	201	extern int tmem_flush_page(struct tmem_pool , struct tmem_oid ,
	202	uint32_t index);
	203	extern int tmem_flush_object(struct tmem_pool , struct tmem_oid );
	204	extern int tmem_destroy_pool(struct tmem_pool *);
	205	extern void tmem_new_pool(struct tmem_pool *, uint32_t);
	206	#endif /* _TMEM_H */