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

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ELEVATOR_H
#define _ELEVATOR_H

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

struct io_cq;
struct elevator_type;
struct blk_mq_debugfs_attr;

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

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 *);
	int (*init_hctx)(struct blk_mq_hw_ctx *, unsigned int);
	void (*exit_hctx)(struct blk_mq_hw_ctx *, unsigned int);
	void (*depth_updated)(struct blk_mq_hw_ctx *);

	bool (*allow_merge)(struct request_queue *, struct request *, struct bio *);
	bool (*bio_merge)(struct request_queue *, struct bio *, unsigned int);
	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 *);
	void (*limit_depth)(unsigned int, struct blk_mq_alloc_data *);
	void (*prepare_request)(struct request *);
	void (*finish_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 request *, u64);
	void (*requeue_request)(struct request *);
	struct request *(*former_request)(struct request_queue *, struct request *);
	struct request *(*next_request)(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 */
	struct elevator_mq_ops ops;

	size_t icq_size;	/* see iocontext.h */
	size_t icq_align;	/* ditto */
	struct elv_fs_entry *elevator_attrs;
	const char *elevator_name;
	const char *elevator_alias;
	const unsigned int elevator_features;
	struct module *elevator_owner;
#ifdef CONFIG_BLK_DEBUG_FS
	const struct blk_mq_debugfs_attr *queue_debugfs_attrs;
	const struct blk_mq_debugfs_attr *hctx_debugfs_attrs;
#endif

	/* managed by elevator core */
	char icq_cache_name[ELV_NAME_MAX + 6];	/* 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;
	DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
};

/*
 * block elevator interface
 */
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 bool elv_attempt_insert_merge(struct request_queue *, struct request *,
				     struct list_head *);
extern struct request *elv_former_request(struct request_queue *, struct request *);
extern struct request *elv_latter_request(struct request_queue *, struct request *);
void elevator_init_mq(struct request_queue *q);

/*
 * 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(struct request_queue *, char *);
extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);

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

#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)

#endif /* _ELEVATOR_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
2e9bc346 CH	2	#ifndef _ELEVATOR_H
2e9bc346 CH	3	#define _ELEVATOR_H
1da177e4	4
4a893e83	5	#include <linux/percpu.h>
242d98f0	6	#include <linux/hashtable.h>
4a893e83	7
7e5a8794	8	struct io_cq;
d50235b7	9	struct elevator_type;
d332ce09	10	struct blk_mq_debugfs_attr;
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	};
34fe7c05 CH	21
bd166ef1 JA	22	struct blk_mq_alloc_data;
	23	struct blk_mq_hw_ctx;
	24
	25	struct elevator_mq_ops {
	26	int (init_sched)(struct request_queue , struct elevator_type *);
	27	void (exit_sched)(struct elevator_queue );
ee056f98 OS	28	int (init_hctx)(struct blk_mq_hw_ctx , unsigned int);
ee056f98 OS	29	void (exit_hctx)(struct blk_mq_hw_ctx , unsigned int);
77f1e0a5	30	void (depth_updated)(struct blk_mq_hw_ctx );
bd166ef1 JA	31
bd166ef1 JA	32	bool (allow_merge)(struct request_queue , struct request , struct bio );
efed9a33	33	bool (bio_merge)(struct request_queue , struct bio *, unsigned int);
bd166ef1	34	int (request_merge)(struct request_queue q, struct request *, struct bio );
34fe7c05	35	void (request_merged)(struct request_queue , struct request *, enum elv_merge);
bd166ef1	36	void (requests_merged)(struct request_queue , struct request , struct request );
5bbf4e5a	37	void (limit_depth)(unsigned int, struct blk_mq_alloc_data );
5d9c305b	38	void (prepare_request)(struct request );
7b9e9361	39	void (finish_request)(struct request );
bd166ef1	40	void (insert_requests)(struct blk_mq_hw_ctx , struct list_head *, bool);
c13660a0	41	struct request (dispatch_request)(struct blk_mq_hw_ctx *);
bd166ef1	42	bool (has_work)(struct blk_mq_hw_ctx );
ed88660a	43	void (completed_request)(struct request , u64);
bd166ef1 JA	44	void (requeue_request)(struct request );
	45	struct request (former_request)(struct request_queue , struct request );
	46	struct request (next_request)(struct request_queue , struct request );
bd166ef1 JA	47	void (init_icq)(struct io_cq );
	48	void (exit_icq)(struct io_cq );
	49	};
	50
1da177e4 LT	51	#define ELV_NAME_MAX (16)
1da177e4 LT	52
e572ec7e AV	53	struct elv_fs_entry {
e572ec7e AV	54	struct attribute attr;
b374d18a JA	55	ssize_t (show)(struct elevator_queue , char *);
b374d18a JA	56	ssize_t (store)(struct elevator_queue , const char *, size_t);
e572ec7e AV	57	};
e572ec7e AV	58
1da177e4 LT	59	/*
	60	* identifies an elevator type, such as AS or deadline
	61	*/
	62	struct elevator_type
	63	{
3d3c2379 TH	64	/* managed by elevator core */
	65	struct kmem_cache *icq_cache;
	66
	67	/* fields provided by elevator implementation */
f9cd4bfe	68	struct elevator_mq_ops ops;
a1ce35fa	69
f1f8cc94 TH	70	size_t icq_size; /* see iocontext.h */
f1f8cc94 TH	71	size_t icq_align; /* ditto */
e572ec7e	72	struct elv_fs_entry *elevator_attrs;
9305d5d7	73	const char *elevator_name;
8ac0d9a8	74	const char *elevator_alias;
68c43f13	75	const unsigned int elevator_features;
1da177e4	76	struct module *elevator_owner;
d332ce09 OS	77	#ifdef CONFIG_BLK_DEBUG_FS
	78	const struct blk_mq_debugfs_attr *queue_debugfs_attrs;
	79	const struct blk_mq_debugfs_attr *hctx_debugfs_attrs;
	80	#endif
3d3c2379 TH	81
3d3c2379 TH	82	/* managed by elevator core */
9bd2bbc0	83	char icq_cache_name[ELV_NAME_MAX + 6]; /* elvname + "_io_cq" */
22f746e2	84	struct list_head list;
1da177e4 LT	85	};
1da177e4 LT	86
242d98f0 SL	87	#define ELV_HASH_BITS 6
242d98f0 SL	88
70b3ea05 JA	89	void elv_rqhash_del(struct request_queue q, struct request rq);
	90	void elv_rqhash_add(struct request_queue q, struct request rq);
	91	void elv_rqhash_reposition(struct request_queue q, struct request rq);
	92	struct request elv_rqhash_find(struct request_queue q, sector_t offset);
	93
1da177e4	94	/*
54069588	95	* each queue has an elevator_queue associated with it
1da177e4 LT	96	*/
	97	struct elevator_queue
	98	{
22f746e2	99	struct elevator_type *type;
1da177e4 LT	100	void *elevator_data;
1da177e4 LT	101	struct kobject kobj;
3d1ab40f	102	struct mutex sysfs_lock;
430c62fb	103	unsigned int registered:1;
242d98f0	104	DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
1da177e4 LT	105	};
	106
	107	/*
	108	* block elevator interface
	109	*/
34fe7c05 CH	110	extern enum elv_merge elv_merge(struct request_queue , struct request *,
34fe7c05 CH	111	struct bio *);
165125e1	112	extern void elv_merge_requests(struct request_queue , struct request ,
1da177e4	113	struct request *);
34fe7c05 CH	114	extern void elv_merged_request(struct request_queue , struct request ,
34fe7c05 CH	115	enum elv_merge);
fd2ef39c JK	116	extern bool elv_attempt_insert_merge(struct request_queue , struct request ,
fd2ef39c JK	117	struct list_head *);
165125e1 JA	118	extern struct request elv_former_request(struct request_queue , struct request *);
165125e1 JA	119	extern struct request elv_latter_request(struct request_queue , struct request *);
26a9750a	120	void elevator_init_mq(struct request_queue *q);
1da177e4 LT	121
	122	/*
	123	* io scheduler registration
	124	*/
e567bf71	125	extern int elv_register(struct elevator_type *);
1da177e4 LT	126	extern void elv_unregister(struct elevator_type *);
	127
	128	/*
	129	* io scheduler sysfs switching
	130	*/
165125e1 JA	131	extern ssize_t elv_iosched_show(struct request_queue , char );
165125e1 JA	132	extern ssize_t elv_iosched_store(struct request_queue , const char , size_t);
1da177e4	133
72ef799b	134	extern bool elv_bio_merge_ok(struct request , struct bio );
d50235b7 JM	135	extern struct elevator_queue elevator_alloc(struct request_queue ,
d50235b7 JM	136	struct elevator_type *);
1da177e4	137
2e662b65 JA	138	/*
	139	* Helper functions.
	140	*/
165125e1 JA	141	extern struct request elv_rb_former_request(struct request_queue , struct request *);
165125e1 JA	142	extern struct request elv_rb_latter_request(struct request_queue , struct request *);
2e662b65 JA	143
	144	/*
	145	* rb support functions.
	146	*/
796d5116	147	extern void elv_rb_add(struct rb_root , struct request );
2e662b65 JA	148	extern void elv_rb_del(struct rb_root , struct request );
	149	extern struct request elv_rb_find(struct rb_root , sector_t);
	150
1da177e4 LT	151	/*
	152	* Insertion selection
	153	*/
	154	#define ELEVATOR_INSERT_FRONT 1
	155	#define ELEVATOR_INSERT_BACK 2
	156	#define ELEVATOR_INSERT_SORT 3
797e7dbb	157	#define ELEVATOR_INSERT_REQUEUE 4
ae1b1539	158	#define ELEVATOR_INSERT_FLUSH 5
5e84ea3a	159	#define ELEVATOR_INSERT_SORT_MERGE 6
1da177e4	160
2e662b65	161	#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
1b47f531	162
1fbfdfcd	163	#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
d9a74df5	164	#define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
1fbfdfcd	165
2e9bc346	166	#endif /* _ELEVATOR_H */