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

#ifndef _LINUX_ELEVATOR_H
#define _LINUX_ELEVATOR_H

typedef int (elevator_merge_fn) (request_queue_t *, struct request **,
				 struct bio *);

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

typedef void (elevator_merged_fn) (request_queue_t *, struct request *);

typedef int (elevator_dispatch_fn) (request_queue_t *, int);

typedef void (elevator_add_req_fn) (request_queue_t *, struct request *);
typedef int (elevator_queue_empty_fn) (request_queue_t *);
typedef struct request *(elevator_request_list_fn) (request_queue_t *, struct request *);
typedef void (elevator_completed_req_fn) (request_queue_t *, struct request *);
typedef int (elevator_may_queue_fn) (request_queue_t *, int, struct bio *);

typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, struct bio *, gfp_t);
typedef void (elevator_put_req_fn) (request_queue_t *, struct request *);
typedef void (elevator_activate_req_fn) (request_queue_t *, struct request *);
typedef void (elevator_deactivate_req_fn) (request_queue_t *, struct request *);

typedef void *(elevator_init_fn) (request_queue_t *, elevator_t *);
typedef void (elevator_exit_fn) (elevator_t *);

struct elevator_ops
{
	elevator_merge_fn *elevator_merge_fn;
	elevator_merged_fn *elevator_merged_fn;
	elevator_merge_req_fn *elevator_merge_req_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_queue_empty_fn *elevator_queue_empty_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_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;
	void (*trim)(struct io_context *);
};

#define ELV_NAME_MAX	(16)

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

/*
 * identifies an elevator type, such as AS or deadline
 */
struct elevator_type
{
	struct list_head list;
	struct elevator_ops ops;
	struct elevator_type *elevator_type;
	struct elv_fs_entry *elevator_attrs;
	char elevator_name[ELV_NAME_MAX];
	struct module *elevator_owner;
};

/*
 * each queue has an elevator_queue associated with it
 */
struct elevator_queue
{
	struct elevator_ops *ops;
	void *elevator_data;
	struct kobject kobj;
	struct elevator_type *elevator_type;
	struct mutex sysfs_lock;
	struct hlist_head *hash;
};

/*
 * block elevator interface
 */
extern void elv_dispatch_sort(request_queue_t *, struct request *);
extern void elv_dispatch_add_tail(request_queue_t *, struct request *);
extern void elv_add_request(request_queue_t *, struct request *, int, int);
extern void __elv_add_request(request_queue_t *, struct request *, int, int);
extern void elv_insert(request_queue_t *, struct request *, int);
extern int elv_merge(request_queue_t *, struct request **, struct bio *);
extern void elv_merge_requests(request_queue_t *, struct request *,
			       struct request *);
extern void elv_merged_request(request_queue_t *, struct request *);
extern void elv_dequeue_request(request_queue_t *, struct request *);
extern void elv_requeue_request(request_queue_t *, struct request *);
extern int elv_queue_empty(request_queue_t *);
extern struct request *elv_next_request(struct request_queue *q);
extern struct request *elv_former_request(request_queue_t *, struct request *);
extern struct request *elv_latter_request(request_queue_t *, struct request *);
extern int elv_register_queue(request_queue_t *q);
extern void elv_unregister_queue(request_queue_t *q);
extern int elv_may_queue(request_queue_t *, int, struct bio *);
extern void elv_completed_request(request_queue_t *, struct request *);
extern int elv_set_request(request_queue_t *, struct request *, struct bio *, gfp_t);
extern void elv_put_request(request_queue_t *, struct request *);

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

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

extern int elevator_init(request_queue_t *, char *);
extern void elevator_exit(elevator_t *);
extern int elv_rq_merge_ok(struct request *, struct bio *);

/*
 * Return values from elevator merger
 */
#define ELEVATOR_NO_MERGE	0
#define ELEVATOR_FRONT_MERGE	1
#define ELEVATOR_BACK_MERGE	2

/*
 * Insertion selection
 */
#define ELEVATOR_INSERT_FRONT	1
#define ELEVATOR_INSERT_BACK	2
#define ELEVATOR_INSERT_SORT	3
#define ELEVATOR_INSERT_REQUEUE	4

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

#define rq_end_sector(rq)	((rq)->sector + (rq)->nr_sectors)

#endif
Commit	Line	Data
1da177e4 LT	1	#ifndef _LINUX_ELEVATOR_H
	2	#define _LINUX_ELEVATOR_H
	3
	4	typedef int (elevator_merge_fn) (request_queue_t , struct request *,
	5	struct bio *);
	6
	7	typedef void (elevator_merge_req_fn) (request_queue_t , struct request , struct request *);
	8
	9	typedef void (elevator_merged_fn) (request_queue_t , struct request );
	10
8922e16c	11	typedef int (elevator_dispatch_fn) (request_queue_t *, int);
1da177e4	12
8922e16c	13	typedef void (elevator_add_req_fn) (request_queue_t , struct request );
1da177e4	14	typedef int (elevator_queue_empty_fn) (request_queue_t *);
1da177e4 LT	15	typedef struct request (elevator_request_list_fn) (request_queue_t , struct request *);
1da177e4 LT	16	typedef void (elevator_completed_req_fn) (request_queue_t , struct request );
22e2c507	17	typedef int (elevator_may_queue_fn) (request_queue_t , int, struct bio );
1da177e4	18
8267e268	19	typedef int (elevator_set_req_fn) (request_queue_t , struct request , struct bio *, gfp_t);
1da177e4	20	typedef void (elevator_put_req_fn) (request_queue_t , struct request );
8922e16c	21	typedef void (elevator_activate_req_fn) (request_queue_t , struct request );
1da177e4 LT	22	typedef void (elevator_deactivate_req_fn) (request_queue_t , struct request );
1da177e4 LT	23
bc1c1169	24	typedef void (elevator_init_fn) (request_queue_t , elevator_t *);
1da177e4 LT	25	typedef void (elevator_exit_fn) (elevator_t *);
	26
	27	struct elevator_ops
	28	{
	29	elevator_merge_fn *elevator_merge_fn;
	30	elevator_merged_fn *elevator_merged_fn;
	31	elevator_merge_req_fn *elevator_merge_req_fn;
	32
8922e16c	33	elevator_dispatch_fn *elevator_dispatch_fn;
1da177e4	34	elevator_add_req_fn *elevator_add_req_fn;
8922e16c	35	elevator_activate_req_fn *elevator_activate_req_fn;
1da177e4 LT	36	elevator_deactivate_req_fn *elevator_deactivate_req_fn;
	37
	38	elevator_queue_empty_fn *elevator_queue_empty_fn;
	39	elevator_completed_req_fn *elevator_completed_req_fn;
	40
	41	elevator_request_list_fn *elevator_former_req_fn;
	42	elevator_request_list_fn *elevator_latter_req_fn;
	43
	44	elevator_set_req_fn *elevator_set_req_fn;
	45	elevator_put_req_fn *elevator_put_req_fn;
	46
	47	elevator_may_queue_fn *elevator_may_queue_fn;
	48
	49	elevator_init_fn *elevator_init_fn;
	50	elevator_exit_fn *elevator_exit_fn;
e17a9489	51	void (trim)(struct io_context );
1da177e4 LT	52	};
	53
	54	#define ELV_NAME_MAX (16)
	55
e572ec7e AV	56	struct elv_fs_entry {
	57	struct attribute attr;
	58	ssize_t (show)(elevator_t , char *);
	59	ssize_t (store)(elevator_t , const char *, size_t);
	60	};
	61
1da177e4 LT	62	/*
	63	* identifies an elevator type, such as AS or deadline
	64	*/
	65	struct elevator_type
	66	{
	67	struct list_head list;
	68	struct elevator_ops ops;
	69	struct elevator_type *elevator_type;
e572ec7e	70	struct elv_fs_entry *elevator_attrs;
1da177e4 LT	71	char elevator_name[ELV_NAME_MAX];
	72	struct module *elevator_owner;
	73	};
	74
	75	/*
54069588	76	* each queue has an elevator_queue associated with it
1da177e4 LT	77	*/
	78	struct elevator_queue
	79	{
	80	struct elevator_ops *ops;
	81	void *elevator_data;
	82	struct kobject kobj;
	83	struct elevator_type *elevator_type;
3d1ab40f	84	struct mutex sysfs_lock;
9817064b	85	struct hlist_head *hash;
1da177e4 LT	86	};
	87
	88	/*
	89	* block elevator interface
	90	*/
1b47f531	91	extern void elv_dispatch_sort(request_queue_t , struct request );
9817064b	92	extern void elv_dispatch_add_tail(request_queue_t , struct request );
1da177e4 LT	93	extern void elv_add_request(request_queue_t , struct request , int, int);
1da177e4 LT	94	extern void __elv_add_request(request_queue_t , struct request , int, int);
30e9656c	95	extern void elv_insert(request_queue_t , struct request , int);
1da177e4 LT	96	extern int elv_merge(request_queue_t , struct request , struct bio );
	97	extern void elv_merge_requests(request_queue_t , struct request ,
	98	struct request *);
	99	extern void elv_merged_request(request_queue_t , struct request );
8922e16c	100	extern void elv_dequeue_request(request_queue_t , struct request );
1da177e4	101	extern void elv_requeue_request(request_queue_t , struct request );
1da177e4 LT	102	extern int elv_queue_empty(request_queue_t *);
	103	extern struct request elv_next_request(struct request_queue q);
	104	extern struct request elv_former_request(request_queue_t , struct request *);
	105	extern struct request elv_latter_request(request_queue_t , struct request *);
	106	extern int elv_register_queue(request_queue_t *q);
	107	extern void elv_unregister_queue(request_queue_t *q);
22e2c507	108	extern int elv_may_queue(request_queue_t , int, struct bio );
1da177e4	109	extern void elv_completed_request(request_queue_t , struct request );
8267e268	110	extern int elv_set_request(request_queue_t , struct request , struct bio *, gfp_t);
1da177e4 LT	111	extern void elv_put_request(request_queue_t , struct request );
	112
	113	/*
	114	* io scheduler registration
	115	*/
	116	extern int elv_register(struct elevator_type *);
	117	extern void elv_unregister(struct elevator_type *);
	118
	119	/*
	120	* io scheduler sysfs switching
	121	*/
	122	extern ssize_t elv_iosched_show(request_queue_t , char );
	123	extern ssize_t elv_iosched_store(request_queue_t , const char , size_t);
	124
	125	extern int elevator_init(request_queue_t , char );
	126	extern void elevator_exit(elevator_t *);
	127	extern int elv_rq_merge_ok(struct request , struct bio );
1da177e4 LT	128
	129	/*
	130	* Return values from elevator merger
	131	*/
	132	#define ELEVATOR_NO_MERGE 0
	133	#define ELEVATOR_FRONT_MERGE 1
	134	#define ELEVATOR_BACK_MERGE 2
	135
	136	/*
	137	* Insertion selection
	138	*/
	139	#define ELEVATOR_INSERT_FRONT 1
	140	#define ELEVATOR_INSERT_BACK 2
	141	#define ELEVATOR_INSERT_SORT 3
797e7dbb	142	#define ELEVATOR_INSERT_REQUEUE 4
1da177e4 LT	143
	144	/*
	145	* return values from elevator_may_queue_fn
	146	*/
	147	enum {
	148	ELV_MQUEUE_MAY,
	149	ELV_MQUEUE_NO,
	150	ELV_MQUEUE_MUST,
	151	};
	152
1b47f531 JA	153	#define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors)
1b47f531 JA	154
1da177e4	155	#endif