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

/* SPDX-License-Identifier: GPL-2.0 */
#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;
#ifdef CONFIG_BLK_DEBUG_FS
struct blk_mq_debugfs_attr;
#endif

/*
 * 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 blk_mq_hw_ctx *, 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 *, struct bio *bio);
	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 *);
extern struct request *elv_former_request(struct request_queue *, struct request *);
extern struct request *elv_latter_request(struct request_queue *, 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(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 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)

/*
 * Elevator features.
 */

/* Supports zoned block devices sequential write constraint */
#define ELEVATOR_F_ZBD_SEQ_WRITE	(1U << 0)

#endif /* CONFIG_BLOCK */
#endif
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1da177e4 LT	2	#ifndef _LINUX_ELEVATOR_H
	3	#define _LINUX_ELEVATOR_H
	4
4a893e83	5	#include <linux/percpu.h>
242d98f0	6	#include <linux/hashtable.h>
4a893e83	7
9361401e DH	8	#ifdef CONFIG_BLOCK
9361401e DH	9
7e5a8794	10	struct io_cq;
d50235b7	11	struct elevator_type;
d332ce09 OS	12	#ifdef CONFIG_BLK_DEBUG_FS
	13	struct blk_mq_debugfs_attr;
	14	#endif
7e5a8794	15
34fe7c05 CH	16	/*
	17	* Return values from elevator merger
	18	*/
	19	enum elv_merge {
	20	ELEVATOR_NO_MERGE = 0,
	21	ELEVATOR_FRONT_MERGE = 1,
	22	ELEVATOR_BACK_MERGE = 2,
1e739730	23	ELEVATOR_DISCARD_MERGE = 3,
34fe7c05 CH	24	};
34fe7c05 CH	25
bd166ef1 JA	26	struct blk_mq_alloc_data;
	27	struct blk_mq_hw_ctx;
	28
	29	struct elevator_mq_ops {
	30	int (init_sched)(struct request_queue , struct elevator_type *);
	31	void (exit_sched)(struct elevator_queue );
ee056f98 OS	32	int (init_hctx)(struct blk_mq_hw_ctx , unsigned int);
ee056f98 OS	33	void (exit_hctx)(struct blk_mq_hw_ctx , unsigned int);
77f1e0a5	34	void (depth_updated)(struct blk_mq_hw_ctx );
bd166ef1 JA	35
bd166ef1 JA	36	bool (allow_merge)(struct request_queue , struct request , struct bio );
14ccb66b	37	bool (bio_merge)(struct blk_mq_hw_ctx , struct bio *, unsigned int);
bd166ef1	38	int (request_merge)(struct request_queue q, struct request *, struct bio );
34fe7c05	39	void (request_merged)(struct request_queue , struct request *, enum elv_merge);
bd166ef1	40	void (requests_merged)(struct request_queue , struct request , struct request );
5bbf4e5a CH	41	void (limit_depth)(unsigned int, struct blk_mq_alloc_data );
5bbf4e5a CH	42	void (prepare_request)(struct request , struct bio *bio);
7b9e9361	43	void (finish_request)(struct request );
bd166ef1	44	void (insert_requests)(struct blk_mq_hw_ctx , struct list_head *, bool);
c13660a0	45	struct request (dispatch_request)(struct blk_mq_hw_ctx *);
bd166ef1	46	bool (has_work)(struct blk_mq_hw_ctx );
ed88660a	47	void (completed_request)(struct request , u64);
bd166ef1 JA	48	void (requeue_request)(struct request );
	49	struct request (former_request)(struct request_queue , struct request );
	50	struct request (next_request)(struct request_queue , struct request );
bd166ef1 JA	51	void (init_icq)(struct io_cq );
	52	void (exit_icq)(struct io_cq );
	53	};
	54
1da177e4 LT	55	#define ELV_NAME_MAX (16)
1da177e4 LT	56
e572ec7e AV	57	struct elv_fs_entry {
e572ec7e AV	58	struct attribute attr;
b374d18a JA	59	ssize_t (show)(struct elevator_queue , char *);
b374d18a JA	60	ssize_t (store)(struct elevator_queue , const char *, size_t);
e572ec7e AV	61	};
e572ec7e AV	62
1da177e4 LT	63	/*
	64	* identifies an elevator type, such as AS or deadline
	65	*/
	66	struct elevator_type
	67	{
3d3c2379 TH	68	/* managed by elevator core */
	69	struct kmem_cache *icq_cache;
	70
	71	/* fields provided by elevator implementation */
f9cd4bfe	72	struct elevator_mq_ops ops;
a1ce35fa	73
f1f8cc94 TH	74	size_t icq_size; /* see iocontext.h */
f1f8cc94 TH	75	size_t icq_align; /* ditto */
e572ec7e	76	struct elv_fs_entry *elevator_attrs;
9305d5d7	77	const char *elevator_name;
8ac0d9a8	78	const char *elevator_alias;
68c43f13	79	const unsigned int elevator_features;
1da177e4	80	struct module *elevator_owner;
d332ce09 OS	81	#ifdef CONFIG_BLK_DEBUG_FS
	82	const struct blk_mq_debugfs_attr *queue_debugfs_attrs;
	83	const struct blk_mq_debugfs_attr *hctx_debugfs_attrs;
	84	#endif
3d3c2379 TH	85
3d3c2379 TH	86	/* managed by elevator core */
9bd2bbc0	87	char icq_cache_name[ELV_NAME_MAX + 6]; /* elvname + "_io_cq" */
22f746e2	88	struct list_head list;
1da177e4 LT	89	};
1da177e4 LT	90
242d98f0 SL	91	#define ELV_HASH_BITS 6
242d98f0 SL	92
70b3ea05 JA	93	void elv_rqhash_del(struct request_queue q, struct request rq);
	94	void elv_rqhash_add(struct request_queue q, struct request rq);
	95	void elv_rqhash_reposition(struct request_queue q, struct request rq);
	96	struct request elv_rqhash_find(struct request_queue q, sector_t offset);
	97
1da177e4	98	/*
54069588	99	* each queue has an elevator_queue associated with it
1da177e4 LT	100	*/
	101	struct elevator_queue
	102	{
22f746e2	103	struct elevator_type *type;
1da177e4 LT	104	void *elevator_data;
1da177e4 LT	105	struct kobject kobj;
3d1ab40f	106	struct mutex sysfs_lock;
430c62fb	107	unsigned int registered:1;
242d98f0	108	DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
1da177e4 LT	109	};
	110
	111	/*
	112	* block elevator interface
	113	*/
34fe7c05 CH	114	extern enum elv_merge elv_merge(struct request_queue , struct request *,
34fe7c05 CH	115	struct bio *);
165125e1	116	extern void elv_merge_requests(struct request_queue , struct request ,
1da177e4	117	struct request *);
34fe7c05 CH	118	extern void elv_merged_request(struct request_queue , struct request ,
34fe7c05 CH	119	enum elv_merge);
bd166ef1	120	extern bool elv_attempt_insert_merge(struct request_queue , struct request );
165125e1 JA	121	extern struct request elv_former_request(struct request_queue , struct request *);
165125e1 JA	122	extern struct request elv_latter_request(struct request_queue , struct request *);
1da177e4 LT	123
	124	/*
	125	* io scheduler registration
	126	*/
e567bf71	127	extern int elv_register(struct elevator_type *);
1da177e4 LT	128	extern void elv_unregister(struct elevator_type *);
	129
	130	/*
	131	* io scheduler sysfs switching
	132	*/
165125e1 JA	133	extern ssize_t elv_iosched_show(struct request_queue , char );
165125e1 JA	134	extern ssize_t elv_iosched_store(struct request_queue , const char , size_t);
1da177e4	135
72ef799b	136	extern bool elv_bio_merge_ok(struct request , struct bio );
d50235b7 JM	137	extern struct elevator_queue elevator_alloc(struct request_queue ,
d50235b7 JM	138	struct elevator_type *);
1da177e4	139
2e662b65 JA	140	/*
	141	* Helper functions.
	142	*/
165125e1 JA	143	extern struct request elv_rb_former_request(struct request_queue , struct request *);
165125e1 JA	144	extern struct request elv_rb_latter_request(struct request_queue , struct request *);
2e662b65 JA	145
	146	/*
	147	* rb support functions.
	148	*/
796d5116	149	extern void elv_rb_add(struct rb_root , struct request );
2e662b65 JA	150	extern void elv_rb_del(struct rb_root , struct request );
	151	extern struct request elv_rb_find(struct rb_root , sector_t);
	152
1da177e4 LT	153	/*
	154	* Insertion selection
	155	*/
	156	#define ELEVATOR_INSERT_FRONT 1
	157	#define ELEVATOR_INSERT_BACK 2
	158	#define ELEVATOR_INSERT_SORT 3
797e7dbb	159	#define ELEVATOR_INSERT_REQUEUE 4
ae1b1539	160	#define ELEVATOR_INSERT_FLUSH 5
5e84ea3a	161	#define ELEVATOR_INSERT_SORT_MERGE 6
1da177e4	162
2e46e8b2	163	#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
2e662b65	164	#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
1b47f531	165
1fbfdfcd	166	#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
d9a74df5	167	#define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
1fbfdfcd	168
68c43f13 DLM	169	/*
	170	* Elevator features.
	171	*/
	172
	173	/* Supports zoned block devices sequential write constraint */
	174	#define ELEVATOR_F_ZBD_SEQ_WRITE (1U << 0)
	175
9361401e	176	#endif /* CONFIG_BLOCK */
1da177e4	177	#endif