[mirror_ubuntu-bionic-kernel.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;

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 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 *);

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;
	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;
};

#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 */
	struct elevator_ops 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;

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

#define ELV_HASH_BITS 6

/*
 * 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;
	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 int 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 *, 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_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_rq_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);

/*
 * 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)

#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
165125e1	12	typedef int (elevator_merge_fn) (struct request_queue , struct request *,
1da177e4 LT	13	struct bio *);
1da177e4 LT	14
165125e1	15	typedef void (elevator_merge_req_fn) (struct request_queue , struct request , struct request *);
1da177e4	16
165125e1	17	typedef void (elevator_merged_fn) (struct request_queue , struct request , int);
1da177e4	18
165125e1	19	typedef int (elevator_allow_merge_fn) (struct request_queue , struct request , struct bio *);
da775265	20
812d4026 DS	21	typedef void (elevator_bio_merged_fn) (struct request_queue *,
	22	struct request , struct bio );
	23
165125e1	24	typedef int (elevator_dispatch_fn) (struct request_queue *, int);
1da177e4	25
165125e1	26	typedef void (elevator_add_req_fn) (struct request_queue , struct request );
165125e1 JA	27	typedef struct request (elevator_request_list_fn) (struct request_queue , struct request *);
	28	typedef void (elevator_completed_req_fn) (struct request_queue , struct request );
	29	typedef int (elevator_may_queue_fn) (struct request_queue *, int);
1da177e4	30
9b84cacd	31	typedef void (elevator_init_icq_fn) (struct io_cq *);
7e5a8794	32	typedef void (elevator_exit_icq_fn) (struct io_cq *);
852c788f TH	33	typedef int (elevator_set_req_fn) (struct request_queue , struct request ,
852c788f TH	34	struct bio *, gfp_t);
bb37b94c	35	typedef void (elevator_put_req_fn) (struct request *);
165125e1 JA	36	typedef void (elevator_activate_req_fn) (struct request_queue , struct request );
165125e1 JA	37	typedef void (elevator_deactivate_req_fn) (struct request_queue , struct request );
1da177e4	38
d50235b7 JM	39	typedef int (elevator_init_fn) (struct request_queue *,
d50235b7 JM	40	struct elevator_type *e);
b374d18a	41	typedef void (elevator_exit_fn) (struct elevator_queue *);
1da177e4 LT	42
	43	struct elevator_ops
	44	{
	45	elevator_merge_fn *elevator_merge_fn;
	46	elevator_merged_fn *elevator_merged_fn;
	47	elevator_merge_req_fn *elevator_merge_req_fn;
da775265	48	elevator_allow_merge_fn *elevator_allow_merge_fn;
812d4026	49	elevator_bio_merged_fn *elevator_bio_merged_fn;
1da177e4	50
8922e16c	51	elevator_dispatch_fn *elevator_dispatch_fn;
1da177e4	52	elevator_add_req_fn *elevator_add_req_fn;
8922e16c	53	elevator_activate_req_fn *elevator_activate_req_fn;
1da177e4 LT	54	elevator_deactivate_req_fn *elevator_deactivate_req_fn;
1da177e4 LT	55
1da177e4 LT	56	elevator_completed_req_fn *elevator_completed_req_fn;
	57
	58	elevator_request_list_fn *elevator_former_req_fn;
	59	elevator_request_list_fn *elevator_latter_req_fn;
	60
f1f8cc94 TH	61	elevator_init_icq_fn elevator_init_icq_fn; / see iocontext.h */
f1f8cc94 TH	62	elevator_exit_icq_fn elevator_exit_icq_fn; / ditto */
7e5a8794	63
1da177e4 LT	64	elevator_set_req_fn *elevator_set_req_fn;
	65	elevator_put_req_fn *elevator_put_req_fn;
	66
	67	elevator_may_queue_fn *elevator_may_queue_fn;
	68
	69	elevator_init_fn *elevator_init_fn;
	70	elevator_exit_fn *elevator_exit_fn;
	71	};
	72
	73	#define ELV_NAME_MAX (16)
	74
e572ec7e AV	75	struct elv_fs_entry {
e572ec7e AV	76	struct attribute attr;
b374d18a JA	77	ssize_t (show)(struct elevator_queue , char *);
b374d18a JA	78	ssize_t (store)(struct elevator_queue , const char *, size_t);
e572ec7e AV	79	};
e572ec7e AV	80
1da177e4 LT	81	/*
	82	* identifies an elevator type, such as AS or deadline
	83	*/
	84	struct elevator_type
	85	{
3d3c2379 TH	86	/* managed by elevator core */
	87	struct kmem_cache *icq_cache;
	88
	89	/* fields provided by elevator implementation */
1da177e4	90	struct elevator_ops ops;
f1f8cc94 TH	91	size_t icq_size; /* see iocontext.h */
f1f8cc94 TH	92	size_t icq_align; /* ditto */
e572ec7e	93	struct elv_fs_entry *elevator_attrs;
1da177e4 LT	94	char elevator_name[ELV_NAME_MAX];
1da177e4 LT	95	struct module *elevator_owner;
3d3c2379 TH	96
	97	/* managed by elevator core */
	98	char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */
22f746e2	99	struct list_head list;
1da177e4 LT	100	};
1da177e4 LT	101
242d98f0 SL	102	#define ELV_HASH_BITS 6
242d98f0 SL	103
1da177e4	104	/*
54069588	105	* each queue has an elevator_queue associated with it
1da177e4 LT	106	*/
	107	struct elevator_queue
	108	{
22f746e2	109	struct elevator_type *type;
1da177e4 LT	110	void *elevator_data;
1da177e4 LT	111	struct kobject kobj;
3d1ab40f	112	struct mutex sysfs_lock;
430c62fb	113	unsigned int registered:1;
242d98f0	114	DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
1da177e4 LT	115	};
	116
	117	/*
	118	* block elevator interface
	119	*/
165125e1 JA	120	extern void elv_dispatch_sort(struct request_queue , struct request );
165125e1 JA	121	extern void elv_dispatch_add_tail(struct request_queue , struct request );
7eaceacc JA	122	extern void elv_add_request(struct request_queue , struct request , int);
7eaceacc JA	123	extern void __elv_add_request(struct request_queue , struct request , int);
165125e1 JA	124	extern int elv_merge(struct request_queue , struct request , struct bio );
165125e1 JA	125	extern void elv_merge_requests(struct request_queue , struct request ,
1da177e4	126	struct request *);
165125e1	127	extern void elv_merged_request(struct request_queue , struct request , int);
812d4026 DS	128	extern void elv_bio_merged(struct request_queue q, struct request ,
812d4026 DS	129	struct bio *);
165125e1	130	extern void elv_requeue_request(struct request_queue , struct request );
165125e1 JA	131	extern struct request elv_former_request(struct request_queue , struct request *);
	132	extern struct request elv_latter_request(struct request_queue , struct request *);
	133	extern int elv_register_queue(struct request_queue *q);
	134	extern void elv_unregister_queue(struct request_queue *q);
	135	extern int elv_may_queue(struct request_queue *, int);
	136	extern void elv_completed_request(struct request_queue , struct request );
852c788f TH	137	extern int elv_set_request(struct request_queue q, struct request rq,
852c788f TH	138	struct bio *bio, gfp_t gfp_mask);
165125e1	139	extern void elv_put_request(struct request_queue , struct request );
26308eab	140	extern void elv_drain_elevator(struct request_queue *);
1da177e4 LT	141
	142	/*
	143	* io scheduler registration
	144	*/
bb813f4c	145	extern void __init load_default_elevator_module(void);
e567bf71	146	extern int elv_register(struct elevator_type *);
1da177e4 LT	147	extern void elv_unregister(struct elevator_type *);
	148
	149	/*
	150	* io scheduler sysfs switching
	151	*/
165125e1 JA	152	extern ssize_t elv_iosched_show(struct request_queue , char );
165125e1 JA	153	extern ssize_t elv_iosched_store(struct request_queue , const char , size_t);
1da177e4	154
165125e1	155	extern int elevator_init(struct request_queue , char );
b374d18a	156	extern void elevator_exit(struct elevator_queue *);
5dd531a0	157	extern int elevator_change(struct request_queue , const char );
050c8ea8	158	extern bool elv_rq_merge_ok(struct request , struct bio );
d50235b7 JM	159	extern struct elevator_queue elevator_alloc(struct request_queue ,
d50235b7 JM	160	struct elevator_type *);
1da177e4	161
2e662b65 JA	162	/*
	163	* Helper functions.
	164	*/
165125e1 JA	165	extern struct request elv_rb_former_request(struct request_queue , struct request *);
165125e1 JA	166	extern struct request elv_rb_latter_request(struct request_queue , struct request *);
2e662b65 JA	167
	168	/*
	169	* rb support functions.
	170	*/
796d5116	171	extern void elv_rb_add(struct rb_root , struct request );
2e662b65 JA	172	extern void elv_rb_del(struct rb_root , struct request );
	173	extern struct request elv_rb_find(struct rb_root , sector_t);
	174
1da177e4 LT	175	/*
	176	* Return values from elevator merger
	177	*/
	178	#define ELEVATOR_NO_MERGE 0
	179	#define ELEVATOR_FRONT_MERGE 1
	180	#define ELEVATOR_BACK_MERGE 2
	181
	182	/*
	183	* Insertion selection
	184	*/
	185	#define ELEVATOR_INSERT_FRONT 1
	186	#define ELEVATOR_INSERT_BACK 2
	187	#define ELEVATOR_INSERT_SORT 3
797e7dbb	188	#define ELEVATOR_INSERT_REQUEUE 4
ae1b1539	189	#define ELEVATOR_INSERT_FLUSH 5
5e84ea3a	190	#define ELEVATOR_INSERT_SORT_MERGE 6
1da177e4 LT	191
	192	/*
	193	* return values from elevator_may_queue_fn
	194	*/
	195	enum {
	196	ELV_MQUEUE_MAY,
	197	ELV_MQUEUE_NO,
	198	ELV_MQUEUE_MUST,
	199	};
	200
2e46e8b2	201	#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
2e662b65	202	#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
1b47f531	203
1fbfdfcd	204	#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
d9a74df5	205	#define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
1fbfdfcd	206
bb813f4c TH	207	#else /* CONFIG_BLOCK */
	208
	209	static inline void load_default_elevator_module(void) { }
	210
9361401e	211	#endif /* CONFIG_BLOCK */
1da177e4	212	#endif