[mirror_ubuntu-zesty-kernel.git] / include / linux / elevator.h

#ifndef _LINUX_ELEVATOR_H
#define _LINUX_ELEVATOR_H

#include <linux/percpu.h>

#ifdef CONFIG_BLOCK

typedef int (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 *, int);

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

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 *, int);

typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, 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 void *(elevator_init_fn) (struct request_queue *);
typedef void (elevator_exit_fn) (struct elevator_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_merge_fn *elevator_allow_merge_fn;

	/*
	 * Used for both plugged list and elevator merging and in the
	 * former case called without queue_lock.  Read comment on top of
	 * attempt_plug_merge() for details.
	 */
	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_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;
};

#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
{
	struct list_head list;
	struct elevator_ops ops;
	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;
	unsigned int registered:1;
};

/*
 * 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 int elv_merge(struct request_queue *, struct request **, struct bio *);
extern int elv_try_merge(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 *, int);
extern void elv_bio_merged(struct request_queue *q, struct request *,
				struct bio *);
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 *, int);
extern void elv_abort_queue(struct request_queue *);
extern void elv_completed_request(struct request_queue *, struct request *);
extern int elv_set_request(struct request_queue *, struct request *, gfp_t);
extern void elv_put_request(struct request_queue *, struct request *);
extern void elv_drain_elevator(struct request_queue *);

/*
 * io scheduler registration
 */
extern void 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 int elv_rq_merge_ok(struct request *, struct bio *);

/*
 * 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);

/*
 * 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
#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)

/*
 * Hack to reuse the csd.list list_head as the fifo time holder while
 * the request is in the io scheduler. Saves an unsigned long in rq.
 */
#define rq_fifo_time(rq)	((unsigned long) (rq)->csd.list.next)
#define rq_set_fifo_time(rq,exp)	((rq)->csd.list.next = (void *) (exp))
#define rq_entry_fifo(ptr)	list_entry((ptr), struct request, queuelist)
#define rq_fifo_clear(rq)	do {		\
	list_del_init(&(rq)->queuelist);	\
	INIT_LIST_HEAD(&(rq)->csd.list);	\
	} while (0)

#endif /* CONFIG_BLOCK */
#endif
Commit	Line	Data
1da177e4 LT	1	#ifndef _LINUX_ELEVATOR_H
	2	#define _LINUX_ELEVATOR_H
	3
4a893e83 JA	4	#include <linux/percpu.h>
4a893e83 JA	5
9361401e DH	6	#ifdef CONFIG_BLOCK
9361401e DH	7
165125e1	8	typedef int (elevator_merge_fn) (struct request_queue , struct request *,
1da177e4 LT	9	struct bio *);
1da177e4 LT	10
165125e1	11	typedef void (elevator_merge_req_fn) (struct request_queue , struct request , struct request *);
1da177e4	12
165125e1	13	typedef void (elevator_merged_fn) (struct request_queue , struct request , int);
1da177e4	14
165125e1	15	typedef int (elevator_allow_merge_fn) (struct request_queue , struct request , struct bio *);
da775265	16
812d4026 DS	17	typedef void (elevator_bio_merged_fn) (struct request_queue *,
	18	struct request , struct bio );
	19
165125e1	20	typedef int (elevator_dispatch_fn) (struct request_queue *, int);
1da177e4	21
165125e1	22	typedef void (elevator_add_req_fn) (struct request_queue , struct request );
165125e1 JA	23	typedef struct request (elevator_request_list_fn) (struct request_queue , struct request *);
	24	typedef void (elevator_completed_req_fn) (struct request_queue , struct request );
	25	typedef int (elevator_may_queue_fn) (struct request_queue *, int);
1da177e4	26
165125e1	27	typedef int (elevator_set_req_fn) (struct request_queue , struct request , gfp_t);
bb37b94c	28	typedef void (elevator_put_req_fn) (struct request *);
165125e1 JA	29	typedef void (elevator_activate_req_fn) (struct request_queue , struct request );
165125e1 JA	30	typedef void (elevator_deactivate_req_fn) (struct request_queue , struct request );
1da177e4	31
165125e1	32	typedef void (elevator_init_fn) (struct request_queue );
b374d18a	33	typedef void (elevator_exit_fn) (struct elevator_queue *);
1da177e4 LT	34
	35	struct elevator_ops
	36	{
	37	elevator_merge_fn *elevator_merge_fn;
	38	elevator_merged_fn *elevator_merged_fn;
	39	elevator_merge_req_fn *elevator_merge_req_fn;
da775265	40	elevator_allow_merge_fn *elevator_allow_merge_fn;
bd87b589 TH	41
	42	/*
	43	* Used for both plugged list and elevator merging and in the
	44	* former case called without queue_lock. Read comment on top of
	45	* attempt_plug_merge() for details.
	46	*/
812d4026	47	elevator_bio_merged_fn *elevator_bio_merged_fn;
1da177e4	48
8922e16c	49	elevator_dispatch_fn *elevator_dispatch_fn;
1da177e4	50	elevator_add_req_fn *elevator_add_req_fn;
8922e16c	51	elevator_activate_req_fn *elevator_activate_req_fn;
1da177e4 LT	52	elevator_deactivate_req_fn *elevator_deactivate_req_fn;
1da177e4 LT	53
1da177e4 LT	54	elevator_completed_req_fn *elevator_completed_req_fn;
	55
	56	elevator_request_list_fn *elevator_former_req_fn;
	57	elevator_request_list_fn *elevator_latter_req_fn;
	58
	59	elevator_set_req_fn *elevator_set_req_fn;
	60	elevator_put_req_fn *elevator_put_req_fn;
	61
	62	elevator_may_queue_fn *elevator_may_queue_fn;
	63
	64	elevator_init_fn *elevator_init_fn;
	65	elevator_exit_fn *elevator_exit_fn;
	66	};
	67
	68	#define ELV_NAME_MAX (16)
	69
e572ec7e AV	70	struct elv_fs_entry {
e572ec7e AV	71	struct attribute attr;
b374d18a JA	72	ssize_t (show)(struct elevator_queue , char *);
b374d18a JA	73	ssize_t (store)(struct elevator_queue , const char *, size_t);
e572ec7e AV	74	};
e572ec7e AV	75
1da177e4 LT	76	/*
	77	* identifies an elevator type, such as AS or deadline
	78	*/
	79	struct elevator_type
	80	{
	81	struct list_head list;
	82	struct elevator_ops ops;
e572ec7e	83	struct elv_fs_entry *elevator_attrs;
1da177e4 LT	84	char elevator_name[ELV_NAME_MAX];
	85	struct module *elevator_owner;
	86	};
	87
	88	/*
54069588	89	* each queue has an elevator_queue associated with it
1da177e4 LT	90	*/
	91	struct elevator_queue
	92	{
	93	struct elevator_ops *ops;
	94	void *elevator_data;
	95	struct kobject kobj;
	96	struct elevator_type *elevator_type;
3d1ab40f	97	struct mutex sysfs_lock;
9817064b	98	struct hlist_head *hash;
430c62fb	99	unsigned int registered:1;
1da177e4 LT	100	};
	101
	102	/*
	103	* block elevator interface
	104	*/
165125e1 JA	105	extern void elv_dispatch_sort(struct request_queue , struct request );
165125e1 JA	106	extern void elv_dispatch_add_tail(struct request_queue , struct request );
7eaceacc JA	107	extern void elv_add_request(struct request_queue , struct request , int);
7eaceacc JA	108	extern void __elv_add_request(struct request_queue , struct request , int);
165125e1	109	extern int elv_merge(struct request_queue , struct request , struct bio );
73c10101	110	extern int elv_try_merge(struct request , struct bio );
165125e1	111	extern void elv_merge_requests(struct request_queue , struct request ,
1da177e4	112	struct request *);
165125e1	113	extern void elv_merged_request(struct request_queue , struct request , int);
812d4026 DS	114	extern void elv_bio_merged(struct request_queue q, struct request ,
812d4026 DS	115	struct bio *);
165125e1	116	extern void elv_requeue_request(struct request_queue , struct request );
165125e1 JA	117	extern struct request elv_former_request(struct request_queue , struct request *);
	118	extern struct request elv_latter_request(struct request_queue , struct request *);
	119	extern int elv_register_queue(struct request_queue *q);
	120	extern void elv_unregister_queue(struct request_queue *q);
	121	extern int elv_may_queue(struct request_queue *, int);
11914a53	122	extern void elv_abort_queue(struct request_queue *);
165125e1 JA	123	extern void elv_completed_request(struct request_queue , struct request );
	124	extern int elv_set_request(struct request_queue , struct request , gfp_t);
	125	extern void elv_put_request(struct request_queue , struct request );
26308eab	126	extern void elv_drain_elevator(struct request_queue *);
1da177e4 LT	127
	128	/*
	129	* io scheduler registration
	130	*/
2fdd82bd	131	extern void elv_register(struct elevator_type *);
1da177e4 LT	132	extern void elv_unregister(struct elevator_type *);
	133
	134	/*
	135	* io scheduler sysfs switching
	136	*/
165125e1 JA	137	extern ssize_t elv_iosched_show(struct request_queue , char );
165125e1 JA	138	extern ssize_t elv_iosched_store(struct request_queue , const char , size_t);
1da177e4	139
165125e1	140	extern int elevator_init(struct request_queue , char );
b374d18a	141	extern void elevator_exit(struct elevator_queue *);
5dd531a0	142	extern int elevator_change(struct request_queue , const char );
1da177e4	143	extern int elv_rq_merge_ok(struct request , struct bio );
1da177e4	144
2e662b65 JA	145	/*
	146	* Helper functions.
	147	*/
165125e1 JA	148	extern struct request elv_rb_former_request(struct request_queue , struct request *);
165125e1 JA	149	extern struct request elv_rb_latter_request(struct request_queue , struct request *);
2e662b65 JA	150
	151	/*
	152	* rb support functions.
	153	*/
796d5116	154	extern void elv_rb_add(struct rb_root , struct request );
2e662b65 JA	155	extern void elv_rb_del(struct rb_root , struct request );
	156	extern struct request elv_rb_find(struct rb_root , sector_t);
	157
1da177e4 LT	158	/*
	159	* Return values from elevator merger
	160	*/
	161	#define ELEVATOR_NO_MERGE 0
	162	#define ELEVATOR_FRONT_MERGE 1
	163	#define ELEVATOR_BACK_MERGE 2
	164
	165	/*
	166	* Insertion selection
	167	*/
	168	#define ELEVATOR_INSERT_FRONT 1
	169	#define ELEVATOR_INSERT_BACK 2
	170	#define ELEVATOR_INSERT_SORT 3
797e7dbb	171	#define ELEVATOR_INSERT_REQUEUE 4
ae1b1539	172	#define ELEVATOR_INSERT_FLUSH 5
5e84ea3a	173	#define ELEVATOR_INSERT_SORT_MERGE 6
1da177e4 LT	174
	175	/*
	176	* return values from elevator_may_queue_fn
	177	*/
	178	enum {
	179	ELV_MQUEUE_MAY,
	180	ELV_MQUEUE_NO,
	181	ELV_MQUEUE_MUST,
	182	};
	183
2e46e8b2	184	#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
2e662b65	185	#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
1b47f531	186
1fbfdfcd	187	/*
c7c22e4d	188	* Hack to reuse the csd.list list_head as the fifo time holder while
1fbfdfcd JA	189	* the request is in the io scheduler. Saves an unsigned long in rq.
1fbfdfcd JA	190	*/
c7c22e4d JA	191	#define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next)
c7c22e4d JA	192	#define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp))
1fbfdfcd JA	193	#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
	194	#define rq_fifo_clear(rq) do { \
	195	list_del_init(&(rq)->queuelist); \
c7c22e4d	196	INIT_LIST_HEAD(&(rq)->csd.list); \
1fbfdfcd JA	197	} while (0)
1fbfdfcd JA	198
9361401e	199	#endif /* CONFIG_BLOCK */
1da177e4	200	#endif