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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_ELEVATOR_H
2#define _LINUX_ELEVATOR_H
3
Jens Axboe4a893e82006-07-22 15:37:43 +02004#include <linux/percpu.h>
Sasha Levin242d98f2012-12-17 10:01:27 -05005#include <linux/hashtable.h>
Jens Axboe4a893e82006-07-22 15:37:43 +02006
David Howells93614012006-09-30 20:45:40 +02007#ifdef CONFIG_BLOCK
8
Tejun Heo7e5a8792011-12-14 00:33:42 +01009struct io_cq;
Jianpeng Mad50235b2013-07-03 13:25:24 +020010struct elevator_type;
Tejun Heo7e5a8792011-12-14 00:33:42 +010011
Jens Axboe165125e2007-07-24 09:28:11 +020012typedef int (elevator_merge_fn) (struct request_queue *, struct request **,
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 struct bio *);
14
Jens Axboe165125e2007-07-24 09:28:11 +020015typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070016
Jens Axboe165125e2007-07-24 09:28:11 +020017typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
Tahsin Erdogan72ef7992016-07-07 11:48:22 -070019typedef int (elevator_allow_bio_merge_fn) (struct request_queue *,
20 struct request *, struct bio *);
21
22typedef int (elevator_allow_rq_merge_fn) (struct request_queue *,
23 struct request *, struct request *);
Jens Axboeda775262006-12-20 11:04:12 +010024
Divyesh Shah812d4022010-04-08 21:14:23 -070025typedef void (elevator_bio_merged_fn) (struct request_queue *,
26 struct request *, struct bio *);
27
Jens Axboe165125e2007-07-24 09:28:11 +020028typedef int (elevator_dispatch_fn) (struct request_queue *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
Jens Axboe165125e2007-07-24 09:28:11 +020030typedef void (elevator_add_req_fn) (struct request_queue *, struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +020031typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *);
32typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *);
Mike Christieba568ea2016-06-05 14:32:13 -050033typedef int (elevator_may_queue_fn) (struct request_queue *, int, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
Tejun Heo9b84cac2011-12-14 00:33:42 +010035typedef void (elevator_init_icq_fn) (struct io_cq *);
Tejun Heo7e5a8792011-12-14 00:33:42 +010036typedef void (elevator_exit_icq_fn) (struct io_cq *);
Tejun Heo852c7882012-03-05 13:15:27 -080037typedef int (elevator_set_req_fn) (struct request_queue *, struct request *,
38 struct bio *, gfp_t);
Jens Axboebb37b942006-12-01 10:42:33 +010039typedef void (elevator_put_req_fn) (struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +020040typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
41typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
Jianpeng Mad50235b2013-07-03 13:25:24 +020043typedef int (elevator_init_fn) (struct request_queue *,
44 struct elevator_type *e);
Jens Axboeb374d182008-10-31 10:05:07 +010045typedef void (elevator_exit_fn) (struct elevator_queue *);
Jens Axboe0bb97942015-06-10 08:01:20 -060046typedef void (elevator_registered_fn) (struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
48struct elevator_ops
49{
50 elevator_merge_fn *elevator_merge_fn;
51 elevator_merged_fn *elevator_merged_fn;
52 elevator_merge_req_fn *elevator_merge_req_fn;
Tahsin Erdogan72ef7992016-07-07 11:48:22 -070053 elevator_allow_bio_merge_fn *elevator_allow_bio_merge_fn;
54 elevator_allow_rq_merge_fn *elevator_allow_rq_merge_fn;
Divyesh Shah812d4022010-04-08 21:14:23 -070055 elevator_bio_merged_fn *elevator_bio_merged_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
Tejun Heo8922e162005-10-20 16:23:44 +020057 elevator_dispatch_fn *elevator_dispatch_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 elevator_add_req_fn *elevator_add_req_fn;
Tejun Heo8922e162005-10-20 16:23:44 +020059 elevator_activate_req_fn *elevator_activate_req_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070060 elevator_deactivate_req_fn *elevator_deactivate_req_fn;
61
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 elevator_completed_req_fn *elevator_completed_req_fn;
63
64 elevator_request_list_fn *elevator_former_req_fn;
65 elevator_request_list_fn *elevator_latter_req_fn;
66
Tejun Heof1f8cc92011-12-14 00:33:42 +010067 elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */
68 elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */
Tejun Heo7e5a8792011-12-14 00:33:42 +010069
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 elevator_set_req_fn *elevator_set_req_fn;
71 elevator_put_req_fn *elevator_put_req_fn;
72
73 elevator_may_queue_fn *elevator_may_queue_fn;
74
75 elevator_init_fn *elevator_init_fn;
76 elevator_exit_fn *elevator_exit_fn;
Jens Axboe0bb97942015-06-10 08:01:20 -060077 elevator_registered_fn *elevator_registered_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070078};
79
80#define ELV_NAME_MAX (16)
81
Al Viroe572ec72006-03-18 22:27:18 -050082struct elv_fs_entry {
83 struct attribute attr;
Jens Axboeb374d182008-10-31 10:05:07 +010084 ssize_t (*show)(struct elevator_queue *, char *);
85 ssize_t (*store)(struct elevator_queue *, const char *, size_t);
Al Viroe572ec72006-03-18 22:27:18 -050086};
87
Linus Torvalds1da177e2005-04-16 15:20:36 -070088/*
89 * identifies an elevator type, such as AS or deadline
90 */
91struct elevator_type
92{
Tejun Heo3d3c2372011-12-14 00:33:42 +010093 /* managed by elevator core */
94 struct kmem_cache *icq_cache;
95
96 /* fields provided by elevator implementation */
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 struct elevator_ops ops;
Tejun Heof1f8cc92011-12-14 00:33:42 +010098 size_t icq_size; /* see iocontext.h */
99 size_t icq_align; /* ditto */
Al Viroe572ec72006-03-18 22:27:18 -0500100 struct elv_fs_entry *elevator_attrs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 char elevator_name[ELV_NAME_MAX];
102 struct module *elevator_owner;
Tejun Heo3d3c2372011-12-14 00:33:42 +0100103
104 /* managed by elevator core */
105 char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */
Tejun Heo22f746e2011-12-14 00:33:41 +0100106 struct list_head list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107};
108
Sasha Levin242d98f2012-12-17 10:01:27 -0500109#define ELV_HASH_BITS 6
110
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111/*
Adrian Bunk54069582006-01-10 00:09:36 +0100112 * each queue has an elevator_queue associated with it
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 */
114struct elevator_queue
115{
Tejun Heo22f746e2011-12-14 00:33:41 +0100116 struct elevator_type *type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 void *elevator_data;
118 struct kobject kobj;
Al Viro3d1ab402006-03-18 18:35:43 -0500119 struct mutex sysfs_lock;
Jens Axboe430c62f2010-10-07 09:35:16 +0200120 unsigned int registered:1;
Sasha Levin242d98f2012-12-17 10:01:27 -0500121 DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122};
123
124/*
125 * block elevator interface
126 */
Jens Axboe165125e2007-07-24 09:28:11 +0200127extern void elv_dispatch_sort(struct request_queue *, struct request *);
128extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
Jens Axboe7eaceac2011-03-10 08:52:07 +0100129extern void elv_add_request(struct request_queue *, struct request *, int);
130extern void __elv_add_request(struct request_queue *, struct request *, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200131extern int elv_merge(struct request_queue *, struct request **, struct bio *);
132extern void elv_merge_requests(struct request_queue *, struct request *,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200134extern void elv_merged_request(struct request_queue *, struct request *, int);
Divyesh Shah812d4022010-04-08 21:14:23 -0700135extern void elv_bio_merged(struct request_queue *q, struct request *,
136 struct bio *);
Jens Axboe165125e2007-07-24 09:28:11 +0200137extern void elv_requeue_request(struct request_queue *, struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200138extern struct request *elv_former_request(struct request_queue *, struct request *);
139extern struct request *elv_latter_request(struct request_queue *, struct request *);
140extern int elv_register_queue(struct request_queue *q);
141extern void elv_unregister_queue(struct request_queue *q);
Mike Christieba568ea2016-06-05 14:32:13 -0500142extern int elv_may_queue(struct request_queue *, int, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200143extern void elv_completed_request(struct request_queue *, struct request *);
Tejun Heo852c7882012-03-05 13:15:27 -0800144extern int elv_set_request(struct request_queue *q, struct request *rq,
145 struct bio *bio, gfp_t gfp_mask);
Jens Axboe165125e2007-07-24 09:28:11 +0200146extern void elv_put_request(struct request_queue *, struct request *);
Jerome Marchand26308ea2009-03-27 10:31:51 +0100147extern void elv_drain_elevator(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148
149/*
150 * io scheduler registration
151 */
Tejun Heobb813f42013-01-18 14:05:56 -0800152extern void __init load_default_elevator_module(void);
Jens Axboee567bf72014-06-22 16:32:48 -0600153extern int elv_register(struct elevator_type *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154extern void elv_unregister(struct elevator_type *);
155
156/*
157 * io scheduler sysfs switching
158 */
Jens Axboe165125e2007-07-24 09:28:11 +0200159extern ssize_t elv_iosched_show(struct request_queue *, char *);
160extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161
Jens Axboe165125e2007-07-24 09:28:11 +0200162extern int elevator_init(struct request_queue *, char *);
Jens Axboeb374d182008-10-31 10:05:07 +0100163extern void elevator_exit(struct elevator_queue *);
Jens Axboe5dd531a2010-08-23 13:52:19 +0200164extern int elevator_change(struct request_queue *, const char *);
Tahsin Erdogan72ef7992016-07-07 11:48:22 -0700165extern bool elv_bio_merge_ok(struct request *, struct bio *);
Jianpeng Mad50235b2013-07-03 13:25:24 +0200166extern struct elevator_queue *elevator_alloc(struct request_queue *,
167 struct elevator_type *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168
169/*
Jens Axboe2e662b62006-07-13 11:55:04 +0200170 * Helper functions.
171 */
Jens Axboe165125e2007-07-24 09:28:11 +0200172extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
173extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);
Jens Axboe2e662b62006-07-13 11:55:04 +0200174
175/*
176 * rb support functions.
177 */
Jeff Moyer796d5112011-06-02 21:19:05 +0200178extern void elv_rb_add(struct rb_root *, struct request *);
Jens Axboe2e662b62006-07-13 11:55:04 +0200179extern void elv_rb_del(struct rb_root *, struct request *);
180extern struct request *elv_rb_find(struct rb_root *, sector_t);
181
182/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 * Return values from elevator merger
184 */
185#define ELEVATOR_NO_MERGE 0
186#define ELEVATOR_FRONT_MERGE 1
187#define ELEVATOR_BACK_MERGE 2
188
189/*
190 * Insertion selection
191 */
192#define ELEVATOR_INSERT_FRONT 1
193#define ELEVATOR_INSERT_BACK 2
194#define ELEVATOR_INSERT_SORT 3
Tejun Heo797e7db2006-01-06 09:51:03 +0100195#define ELEVATOR_INSERT_REQUEUE 4
Tejun Heoae1b1532011-01-25 12:43:54 +0100196#define ELEVATOR_INSERT_FLUSH 5
Jens Axboe5e84ea32011-03-21 10:14:27 +0100197#define ELEVATOR_INSERT_SORT_MERGE 6
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198
199/*
200 * return values from elevator_may_queue_fn
201 */
202enum {
203 ELV_MQUEUE_MAY,
204 ELV_MQUEUE_NO,
205 ELV_MQUEUE_MUST,
206};
207
Tejun Heo2e46e8b2009-05-07 22:24:41 +0900208#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
Jens Axboe2e662b62006-07-13 11:55:04 +0200209#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
Jens Axboe1b47f532005-10-20 16:37:00 +0200210
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200211#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
Frederic Weisbeckerd9a74df2014-02-24 16:39:53 +0100212#define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200213
Tejun Heobb813f42013-01-18 14:05:56 -0800214#else /* CONFIG_BLOCK */
215
216static inline void load_default_elevator_module(void) { }
217
David Howells93614012006-09-30 20:45:40 +0200218#endif /* CONFIG_BLOCK */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219#endif