[linux-2.6-block.git] / include / linux / elevator.h

#ifndef _LINUX_ELEVATOR_H
#define _LINUX_ELEVATOR_H

#include <linux/percpu.h>
#include <linux/hashtable.h>

#ifdef CONFIG_BLOCK

struct io_cq;
struct elevator_type;

/*
 * Return values from elevator merger
 */
enum elv_merge {
	ELEVATOR_NO_MERGE	= 0,
	ELEVATOR_FRONT_MERGE	= 1,
	ELEVATOR_BACK_MERGE	= 2,
	ELEVATOR_DISCARD_MERGE	= 3,
};

typedef enum elv_merge (elevator_merge_fn) (struct request_queue *, struct request **,
				 struct bio *);

typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *);

typedef void (elevator_merged_fn) (struct request_queue *, struct request *, enum elv_merge);

typedef int (elevator_allow_bio_merge_fn) (struct request_queue *,
					   struct request *, struct bio *);

typedef int (elevator_allow_rq_merge_fn) (struct request_queue *,
					  struct request *, struct request *);

typedef void (elevator_bio_merged_fn) (struct request_queue *,
						struct request *, struct bio *);

typedef int (elevator_dispatch_fn) (struct request_queue *, int);

typedef void (elevator_add_req_fn) (struct request_queue *, struct request *);
typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *);
typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *);
typedef int (elevator_may_queue_fn) (struct request_queue *, unsigned int);

typedef void (elevator_init_icq_fn) (struct io_cq *);
typedef void (elevator_exit_icq_fn) (struct io_cq *);
typedef int (elevator_set_req_fn) (struct request_queue *, struct request *,
				   struct bio *, gfp_t);
typedef void (elevator_put_req_fn) (struct request *);
typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);

typedef int (elevator_init_fn) (struct request_queue *,
				struct elevator_type *e);
typedef void (elevator_exit_fn) (struct elevator_queue *);
typedef void (elevator_registered_fn) (struct request_queue *);

struct elevator_ops
{
	elevator_merge_fn *elevator_merge_fn;
	elevator_merged_fn *elevator_merged_fn;
	elevator_merge_req_fn *elevator_merge_req_fn;
	elevator_allow_bio_merge_fn *elevator_allow_bio_merge_fn;
	elevator_allow_rq_merge_fn *elevator_allow_rq_merge_fn;
	elevator_bio_merged_fn *elevator_bio_merged_fn;

	elevator_dispatch_fn *elevator_dispatch_fn;
	elevator_add_req_fn *elevator_add_req_fn;
	elevator_activate_req_fn *elevator_activate_req_fn;
	elevator_deactivate_req_fn *elevator_deactivate_req_fn;

	elevator_completed_req_fn *elevator_completed_req_fn;

	elevator_request_list_fn *elevator_former_req_fn;
	elevator_request_list_fn *elevator_latter_req_fn;

	elevator_init_icq_fn *elevator_init_icq_fn;	/* see iocontext.h */
	elevator_exit_icq_fn *elevator_exit_icq_fn;	/* ditto */

	elevator_set_req_fn *elevator_set_req_fn;
	elevator_put_req_fn *elevator_put_req_fn;

	elevator_may_queue_fn *elevator_may_queue_fn;

	elevator_init_fn *elevator_init_fn;
	elevator_exit_fn *elevator_exit_fn;
	elevator_registered_fn *elevator_registered_fn;
};

struct blk_mq_alloc_data;
struct blk_mq_hw_ctx;

struct elevator_mq_ops {
	int (*init_sched)(struct request_queue *, struct elevator_type *);
	void (*exit_sched)(struct elevator_queue *);

	bool (*allow_merge)(struct request_queue *, struct request *, struct bio *);
	bool (*bio_merge)(struct blk_mq_hw_ctx *, struct bio *);
	int (*request_merge)(struct request_queue *q, struct request **, struct bio *);
	void (*request_merged)(struct request_queue *, struct request *, enum elv_merge);
	void (*requests_merged)(struct request_queue *, struct request *, struct request *);
	struct request *(*get_request)(struct request_queue *, unsigned int, struct blk_mq_alloc_data *);
	void (*put_request)(struct request *);
	void (*insert_requests)(struct blk_mq_hw_ctx *, struct list_head *, bool);
	struct request *(*dispatch_request)(struct blk_mq_hw_ctx *);
	bool (*has_work)(struct blk_mq_hw_ctx *);
	void (*completed_request)(struct blk_mq_hw_ctx *, struct request *);
	void (*started_request)(struct request *);
	void (*requeue_request)(struct request *);
	struct request *(*former_request)(struct request_queue *, struct request *);
	struct request *(*next_request)(struct request_queue *, struct request *);
	int (*get_rq_priv)(struct request_queue *, struct request *, struct bio *);
	void (*put_rq_priv)(struct request_queue *, struct request *);
	void (*init_icq)(struct io_cq *);
	void (*exit_icq)(struct io_cq *);
};

#define ELV_NAME_MAX	(16)

struct elv_fs_entry {
	struct attribute attr;
	ssize_t (*show)(struct elevator_queue *, char *);
	ssize_t (*store)(struct elevator_queue *, const char *, size_t);
};

/*
 * identifies an elevator type, such as AS or deadline
 */
struct elevator_type
{
	/* managed by elevator core */
	struct kmem_cache *icq_cache;

	/* fields provided by elevator implementation */
	union {
		struct elevator_ops sq;
		struct elevator_mq_ops mq;
	} ops;
	size_t icq_size;	/* see iocontext.h */
	size_t icq_align;	/* ditto */
	struct elv_fs_entry *elevator_attrs;
	char elevator_name[ELV_NAME_MAX];
	struct module *elevator_owner;
	bool uses_mq;

	/* managed by elevator core */
	char icq_cache_name[ELV_NAME_MAX + 5];	/* elvname + "_io_cq" */
	struct list_head list;
};

#define ELV_HASH_BITS 6

void elv_rqhash_del(struct request_queue *q, struct request *rq);
void elv_rqhash_add(struct request_queue *q, struct request *rq);
void elv_rqhash_reposition(struct request_queue *q, struct request *rq);
struct request *elv_rqhash_find(struct request_queue *q, sector_t offset);

/*
 * each queue has an elevator_queue associated with it
 */
struct elevator_queue
{
	struct elevator_type *type;
	void *elevator_data;
	struct kobject kobj;
	struct mutex sysfs_lock;
	unsigned int registered:1;
	unsigned int uses_mq:1;
	DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
};

/*
 * block elevator interface
 */
extern void elv_dispatch_sort(struct request_queue *, struct request *);
extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
extern void elv_add_request(struct request_queue *, struct request *, int);
extern void __elv_add_request(struct request_queue *, struct request *, int);
extern enum elv_merge elv_merge(struct request_queue *, struct request **,
		struct bio *);
extern void elv_merge_requests(struct request_queue *, struct request *,
			       struct request *);
extern void elv_merged_request(struct request_queue *, struct request *,
		enum elv_merge);
extern void elv_bio_merged(struct request_queue *q, struct request *,
				struct bio *);
extern bool elv_attempt_insert_merge(struct request_queue *, struct request *);
extern void elv_requeue_request(struct request_queue *, struct request *);
extern struct request *elv_former_request(struct request_queue *, struct request *);
extern struct request *elv_latter_request(struct request_queue *, struct request *);
extern int elv_register_queue(struct request_queue *q);
extern void elv_unregister_queue(struct request_queue *q);
extern int elv_may_queue(struct request_queue *, unsigned int);
extern void elv_completed_request(struct request_queue *, struct request *);
extern int elv_set_request(struct request_queue *q, struct request *rq,
			   struct bio *bio, gfp_t gfp_mask);
extern void elv_put_request(struct request_queue *, struct request *);
extern void elv_drain_elevator(struct request_queue *);

/*
 * io scheduler registration
 */
extern void __init load_default_elevator_module(void);
extern int elv_register(struct elevator_type *);
extern void elv_unregister(struct elevator_type *);

/*
 * io scheduler sysfs switching
 */
extern ssize_t elv_iosched_show(struct request_queue *, char *);
extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);

extern int elevator_init(struct request_queue *, char *);
extern void elevator_exit(struct elevator_queue *);
extern int elevator_change(struct request_queue *, const char *);
extern bool elv_bio_merge_ok(struct request *, struct bio *);
extern struct elevator_queue *elevator_alloc(struct request_queue *,
					struct elevator_type *);

/*
 * Helper functions.
 */
extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);

/*
 * rb support functions.
 */
extern void elv_rb_add(struct rb_root *, struct request *);
extern void elv_rb_del(struct rb_root *, struct request *);
extern struct request *elv_rb_find(struct rb_root *, sector_t);

/*
 * Insertion selection
 */
#define ELEVATOR_INSERT_FRONT	1
#define ELEVATOR_INSERT_BACK	2
#define ELEVATOR_INSERT_SORT	3
#define ELEVATOR_INSERT_REQUEUE	4
#define ELEVATOR_INSERT_FLUSH	5
#define ELEVATOR_INSERT_SORT_MERGE	6

/*
 * return values from elevator_may_queue_fn
 */
enum {
	ELV_MQUEUE_MAY,
	ELV_MQUEUE_NO,
	ELV_MQUEUE_MUST,
};

#define rq_end_sector(rq)	(blk_rq_pos(rq) + blk_rq_sectors(rq))
#define rb_entry_rq(node)	rb_entry((node), struct request, rb_node)

#define rq_entry_fifo(ptr)	list_entry((ptr), struct request, queuelist)
#define rq_fifo_clear(rq)	list_del_init(&(rq)->queuelist)

#else /* CONFIG_BLOCK */

static inline void load_default_elevator_module(void) { }

#endif /* CONFIG_BLOCK */
#endif
Commit	Line	Data
1da177e4 LT	1	#ifndef _LINUX_ELEVATOR_H
	2	#define _LINUX_ELEVATOR_H
	3
4a893e83	4	#include <linux/percpu.h>
242d98f0	5	#include <linux/hashtable.h>
4a893e83	6
9361401e DH	7	#ifdef CONFIG_BLOCK
9361401e DH	8
7e5a8794	9	struct io_cq;
d50235b7	10	struct elevator_type;
7e5a8794	11
34fe7c05 CH	12	/*
	13	* Return values from elevator merger
	14	*/
	15	enum elv_merge {
	16	ELEVATOR_NO_MERGE = 0,
	17	ELEVATOR_FRONT_MERGE = 1,
	18	ELEVATOR_BACK_MERGE = 2,
1e739730	19	ELEVATOR_DISCARD_MERGE = 3,
34fe7c05 CH	20	};
	21
	22	typedef enum elv_merge (elevator_merge_fn) (struct request_queue , struct request *,
1da177e4 LT	23	struct bio *);
1da177e4 LT	24
165125e1	25	typedef void (elevator_merge_req_fn) (struct request_queue , struct request , struct request *);
1da177e4	26
34fe7c05	27	typedef void (elevator_merged_fn) (struct request_queue , struct request , enum elv_merge);
1da177e4	28
72ef799b TE	29	typedef int (elevator_allow_bio_merge_fn) (struct request_queue *,
	30	struct request , struct bio );
	31
	32	typedef int (elevator_allow_rq_merge_fn) (struct request_queue *,
	33	struct request , struct request );
da775265	34
812d4026 DS	35	typedef void (elevator_bio_merged_fn) (struct request_queue *,
	36	struct request , struct bio );
	37
165125e1	38	typedef int (elevator_dispatch_fn) (struct request_queue *, int);
1da177e4	39
165125e1	40	typedef void (elevator_add_req_fn) (struct request_queue , struct request );
165125e1 JA	41	typedef struct request (elevator_request_list_fn) (struct request_queue , struct request *);
165125e1 JA	42	typedef void (elevator_completed_req_fn) (struct request_queue , struct request );
ef295ecf	43	typedef int (elevator_may_queue_fn) (struct request_queue *, unsigned int);
1da177e4	44
9b84cacd	45	typedef void (elevator_init_icq_fn) (struct io_cq *);
7e5a8794	46	typedef void (elevator_exit_icq_fn) (struct io_cq *);
852c788f TH	47	typedef int (elevator_set_req_fn) (struct request_queue , struct request ,
852c788f TH	48	struct bio *, gfp_t);
bb37b94c	49	typedef void (elevator_put_req_fn) (struct request *);
165125e1 JA	50	typedef void (elevator_activate_req_fn) (struct request_queue , struct request );
165125e1 JA	51	typedef void (elevator_deactivate_req_fn) (struct request_queue , struct request );
1da177e4	52
d50235b7 JM	53	typedef int (elevator_init_fn) (struct request_queue *,
d50235b7 JM	54	struct elevator_type *e);
b374d18a	55	typedef void (elevator_exit_fn) (struct elevator_queue *);
0bb97947	56	typedef void (elevator_registered_fn) (struct request_queue *);
1da177e4 LT	57
	58	struct elevator_ops
	59	{
	60	elevator_merge_fn *elevator_merge_fn;
	61	elevator_merged_fn *elevator_merged_fn;
	62	elevator_merge_req_fn *elevator_merge_req_fn;
72ef799b TE	63	elevator_allow_bio_merge_fn *elevator_allow_bio_merge_fn;
72ef799b TE	64	elevator_allow_rq_merge_fn *elevator_allow_rq_merge_fn;
812d4026	65	elevator_bio_merged_fn *elevator_bio_merged_fn;
1da177e4	66
8922e16c	67	elevator_dispatch_fn *elevator_dispatch_fn;
1da177e4	68	elevator_add_req_fn *elevator_add_req_fn;
8922e16c	69	elevator_activate_req_fn *elevator_activate_req_fn;
1da177e4 LT	70	elevator_deactivate_req_fn *elevator_deactivate_req_fn;
1da177e4 LT	71
1da177e4 LT	72	elevator_completed_req_fn *elevator_completed_req_fn;
	73
	74	elevator_request_list_fn *elevator_former_req_fn;
	75	elevator_request_list_fn *elevator_latter_req_fn;
	76
f1f8cc94 TH	77	elevator_init_icq_fn elevator_init_icq_fn; / see iocontext.h */
f1f8cc94 TH	78	elevator_exit_icq_fn elevator_exit_icq_fn; / ditto */
7e5a8794	79
1da177e4 LT	80	elevator_set_req_fn *elevator_set_req_fn;
	81	elevator_put_req_fn *elevator_put_req_fn;
	82
	83	elevator_may_queue_fn *elevator_may_queue_fn;
	84
	85	elevator_init_fn *elevator_init_fn;
	86	elevator_exit_fn *elevator_exit_fn;
0bb97947	87	elevator_registered_fn *elevator_registered_fn;
1da177e4 LT	88	};
1da177e4 LT	89
bd166ef1 JA	90	struct blk_mq_alloc_data;
	91	struct blk_mq_hw_ctx;
	92
	93	struct elevator_mq_ops {
	94	int (init_sched)(struct request_queue , struct elevator_type *);
	95	void (exit_sched)(struct elevator_queue );
	96
	97	bool (allow_merge)(struct request_queue , struct request , struct bio );
	98	bool (bio_merge)(struct blk_mq_hw_ctx , struct bio *);
	99	int (request_merge)(struct request_queue q, struct request *, struct bio );
34fe7c05	100	void (request_merged)(struct request_queue , struct request *, enum elv_merge);
bd166ef1 JA	101	void (requests_merged)(struct request_queue , struct request , struct request );
	102	struct request (get_request)(struct request_queue , unsigned int, struct blk_mq_alloc_data );
	103	void (put_request)(struct request );
	104	void (insert_requests)(struct blk_mq_hw_ctx , struct list_head *, bool);
c13660a0	105	struct request (dispatch_request)(struct blk_mq_hw_ctx *);
bd166ef1 JA	106	bool (has_work)(struct blk_mq_hw_ctx );
	107	void (completed_request)(struct blk_mq_hw_ctx , struct request *);
	108	void (started_request)(struct request );
	109	void (requeue_request)(struct request );
	110	struct request (former_request)(struct request_queue , struct request );
	111	struct request (next_request)(struct request_queue , struct request );
f1ba8261	112	int (get_rq_priv)(struct request_queue , struct request , struct bio );
bd166ef1 JA	113	void (put_rq_priv)(struct request_queue , struct request *);
	114	void (init_icq)(struct io_cq );
	115	void (exit_icq)(struct io_cq );
	116	};
	117
1da177e4 LT	118	#define ELV_NAME_MAX (16)
1da177e4 LT	119
e572ec7e AV	120	struct elv_fs_entry {
e572ec7e AV	121	struct attribute attr;
b374d18a JA	122	ssize_t (show)(struct elevator_queue , char *);
b374d18a JA	123	ssize_t (store)(struct elevator_queue , const char *, size_t);
e572ec7e AV	124	};
e572ec7e AV	125
1da177e4 LT	126	/*
	127	* identifies an elevator type, such as AS or deadline
	128	*/
	129	struct elevator_type
	130	{
3d3c2379 TH	131	/* managed by elevator core */
	132	struct kmem_cache *icq_cache;
	133
	134	/* fields provided by elevator implementation */
c51ca6cf JA	135	union {
c51ca6cf JA	136	struct elevator_ops sq;
bd166ef1	137	struct elevator_mq_ops mq;
c51ca6cf	138	} ops;
f1f8cc94 TH	139	size_t icq_size; /* see iocontext.h */
f1f8cc94 TH	140	size_t icq_align; /* ditto */
e572ec7e	141	struct elv_fs_entry *elevator_attrs;
1da177e4 LT	142	char elevator_name[ELV_NAME_MAX];
1da177e4 LT	143	struct module *elevator_owner;
bd166ef1	144	bool uses_mq;
3d3c2379 TH	145
	146	/* managed by elevator core */
	147	char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */
22f746e2	148	struct list_head list;
1da177e4 LT	149	};
1da177e4 LT	150
242d98f0 SL	151	#define ELV_HASH_BITS 6
242d98f0 SL	152
70b3ea05 JA	153	void elv_rqhash_del(struct request_queue q, struct request rq);
	154	void elv_rqhash_add(struct request_queue q, struct request rq);
	155	void elv_rqhash_reposition(struct request_queue q, struct request rq);
	156	struct request elv_rqhash_find(struct request_queue q, sector_t offset);
	157
1da177e4	158	/*
54069588	159	* each queue has an elevator_queue associated with it
1da177e4 LT	160	*/
	161	struct elevator_queue
	162	{
22f746e2	163	struct elevator_type *type;
1da177e4 LT	164	void *elevator_data;
1da177e4 LT	165	struct kobject kobj;
3d1ab40f	166	struct mutex sysfs_lock;
430c62fb	167	unsigned int registered:1;
bd166ef1	168	unsigned int uses_mq:1;
242d98f0	169	DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
1da177e4 LT	170	};
	171
	172	/*
	173	* block elevator interface
	174	*/
165125e1 JA	175	extern void elv_dispatch_sort(struct request_queue , struct request );
165125e1 JA	176	extern void elv_dispatch_add_tail(struct request_queue , struct request );
7eaceacc JA	177	extern void elv_add_request(struct request_queue , struct request , int);
7eaceacc JA	178	extern void __elv_add_request(struct request_queue , struct request , int);
34fe7c05 CH	179	extern enum elv_merge elv_merge(struct request_queue , struct request *,
34fe7c05 CH	180	struct bio *);
165125e1	181	extern void elv_merge_requests(struct request_queue , struct request ,
1da177e4	182	struct request *);
34fe7c05 CH	183	extern void elv_merged_request(struct request_queue , struct request ,
34fe7c05 CH	184	enum elv_merge);
812d4026 DS	185	extern void elv_bio_merged(struct request_queue q, struct request ,
812d4026 DS	186	struct bio *);
bd166ef1	187	extern bool elv_attempt_insert_merge(struct request_queue , struct request );
165125e1	188	extern void elv_requeue_request(struct request_queue , struct request );
165125e1 JA	189	extern struct request elv_former_request(struct request_queue , struct request *);
	190	extern struct request elv_latter_request(struct request_queue , struct request *);
	191	extern int elv_register_queue(struct request_queue *q);
	192	extern void elv_unregister_queue(struct request_queue *q);
ef295ecf	193	extern int elv_may_queue(struct request_queue *, unsigned int);
165125e1	194	extern void elv_completed_request(struct request_queue , struct request );
852c788f TH	195	extern int elv_set_request(struct request_queue q, struct request rq,
852c788f TH	196	struct bio *bio, gfp_t gfp_mask);
165125e1	197	extern void elv_put_request(struct request_queue , struct request );
26308eab	198	extern void elv_drain_elevator(struct request_queue *);
1da177e4 LT	199
	200	/*
	201	* io scheduler registration
	202	*/
bb813f4c	203	extern void __init load_default_elevator_module(void);
e567bf71	204	extern int elv_register(struct elevator_type *);
1da177e4 LT	205	extern void elv_unregister(struct elevator_type *);
	206
	207	/*
	208	* io scheduler sysfs switching
	209	*/
165125e1 JA	210	extern ssize_t elv_iosched_show(struct request_queue , char );
165125e1 JA	211	extern ssize_t elv_iosched_store(struct request_queue , const char , size_t);
1da177e4	212
165125e1	213	extern int elevator_init(struct request_queue , char );
b374d18a	214	extern void elevator_exit(struct elevator_queue *);
5dd531a0	215	extern int elevator_change(struct request_queue , const char );
72ef799b	216	extern bool elv_bio_merge_ok(struct request , struct bio );
d50235b7 JM	217	extern struct elevator_queue elevator_alloc(struct request_queue ,
d50235b7 JM	218	struct elevator_type *);
1da177e4	219
2e662b65 JA	220	/*
	221	* Helper functions.
	222	*/
165125e1 JA	223	extern struct request elv_rb_former_request(struct request_queue , struct request *);
165125e1 JA	224	extern struct request elv_rb_latter_request(struct request_queue , struct request *);
2e662b65 JA	225
	226	/*
	227	* rb support functions.
	228	*/
796d5116	229	extern void elv_rb_add(struct rb_root , struct request );
2e662b65 JA	230	extern void elv_rb_del(struct rb_root , struct request );
	231	extern struct request elv_rb_find(struct rb_root , sector_t);
	232
1da177e4 LT	233	/*
	234	* Insertion selection
	235	*/
	236	#define ELEVATOR_INSERT_FRONT 1
	237	#define ELEVATOR_INSERT_BACK 2
	238	#define ELEVATOR_INSERT_SORT 3
797e7dbb	239	#define ELEVATOR_INSERT_REQUEUE 4
ae1b1539	240	#define ELEVATOR_INSERT_FLUSH 5
5e84ea3a	241	#define ELEVATOR_INSERT_SORT_MERGE 6
1da177e4 LT	242
	243	/*
	244	* return values from elevator_may_queue_fn
	245	*/
	246	enum {
	247	ELV_MQUEUE_MAY,
	248	ELV_MQUEUE_NO,
	249	ELV_MQUEUE_MUST,
	250	};
	251
2e46e8b2	252	#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
2e662b65	253	#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
1b47f531	254
1fbfdfcd	255	#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
d9a74df5	256	#define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
1fbfdfcd	257
bb813f4c TH	258	#else /* CONFIG_BLOCK */
	259
	260	static inline void load_default_elevator_module(void) { }
	261
9361401e	262	#endif /* CONFIG_BLOCK */
1da177e4	263	#endif