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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>
5
David Howells93614012006-09-30 20:45:40 +02006#ifdef CONFIG_BLOCK
7
Tejun Heo7e5a8792011-12-14 00:33:42 +01008struct io_cq;
9
Jens Axboe165125e2007-07-24 09:28:11 +020010typedef int (elevator_merge_fn) (struct request_queue *, struct request **,
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 struct bio *);
12
Jens Axboe165125e2007-07-24 09:28:11 +020013typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070014
Jens Axboe165125e2007-07-24 09:28:11 +020015typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070016
Jens Axboe165125e2007-07-24 09:28:11 +020017typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *);
Jens Axboeda775262006-12-20 11:04:12 +010018
Divyesh Shah812d4022010-04-08 21:14:23 -070019typedef void (elevator_bio_merged_fn) (struct request_queue *,
20 struct request *, struct bio *);
21
Jens Axboe165125e2007-07-24 09:28:11 +020022typedef int (elevator_dispatch_fn) (struct request_queue *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
Jens Axboe165125e2007-07-24 09:28:11 +020024typedef void (elevator_add_req_fn) (struct request_queue *, struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +020025typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *);
26typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *);
27typedef int (elevator_may_queue_fn) (struct request_queue *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
Tejun Heo9b84cac2011-12-14 00:33:42 +010029typedef void (elevator_init_icq_fn) (struct io_cq *);
Tejun Heo7e5a8792011-12-14 00:33:42 +010030typedef void (elevator_exit_icq_fn) (struct io_cq *);
Jens Axboe165125e2007-07-24 09:28:11 +020031typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, gfp_t);
Jens Axboebb37b942006-12-01 10:42:33 +010032typedef void (elevator_put_req_fn) (struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +020033typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
34typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
Jens Axboe165125e2007-07-24 09:28:11 +020036typedef void *(elevator_init_fn) (struct request_queue *);
Jens Axboeb374d182008-10-31 10:05:07 +010037typedef void (elevator_exit_fn) (struct elevator_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
39struct elevator_ops
40{
41 elevator_merge_fn *elevator_merge_fn;
42 elevator_merged_fn *elevator_merged_fn;
43 elevator_merge_req_fn *elevator_merge_req_fn;
Jens Axboeda775262006-12-20 11:04:12 +010044 elevator_allow_merge_fn *elevator_allow_merge_fn;
Divyesh Shah812d4022010-04-08 21:14:23 -070045 elevator_bio_merged_fn *elevator_bio_merged_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070046
Tejun Heo8922e162005-10-20 16:23:44 +020047 elevator_dispatch_fn *elevator_dispatch_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 elevator_add_req_fn *elevator_add_req_fn;
Tejun Heo8922e162005-10-20 16:23:44 +020049 elevator_activate_req_fn *elevator_activate_req_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 elevator_deactivate_req_fn *elevator_deactivate_req_fn;
51
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 elevator_completed_req_fn *elevator_completed_req_fn;
53
54 elevator_request_list_fn *elevator_former_req_fn;
55 elevator_request_list_fn *elevator_latter_req_fn;
56
Tejun Heof1f8cc92011-12-14 00:33:42 +010057 elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */
58 elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */
Tejun Heo7e5a8792011-12-14 00:33:42 +010059
Linus Torvalds1da177e2005-04-16 15:20:36 -070060 elevator_set_req_fn *elevator_set_req_fn;
61 elevator_put_req_fn *elevator_put_req_fn;
62
63 elevator_may_queue_fn *elevator_may_queue_fn;
64
65 elevator_init_fn *elevator_init_fn;
66 elevator_exit_fn *elevator_exit_fn;
67};
68
69#define ELV_NAME_MAX (16)
70
Al Viroe572ec72006-03-18 22:27:18 -050071struct elv_fs_entry {
72 struct attribute attr;
Jens Axboeb374d182008-10-31 10:05:07 +010073 ssize_t (*show)(struct elevator_queue *, char *);
74 ssize_t (*store)(struct elevator_queue *, const char *, size_t);
Al Viroe572ec72006-03-18 22:27:18 -050075};
76
Linus Torvalds1da177e2005-04-16 15:20:36 -070077/*
78 * identifies an elevator type, such as AS or deadline
79 */
80struct elevator_type
81{
Tejun Heo3d3c2372011-12-14 00:33:42 +010082 /* managed by elevator core */
83 struct kmem_cache *icq_cache;
84
85 /* fields provided by elevator implementation */
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 struct elevator_ops ops;
Tejun Heof1f8cc92011-12-14 00:33:42 +010087 size_t icq_size; /* see iocontext.h */
88 size_t icq_align; /* ditto */
Al Viroe572ec72006-03-18 22:27:18 -050089 struct elv_fs_entry *elevator_attrs;
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 char elevator_name[ELV_NAME_MAX];
91 struct module *elevator_owner;
Tejun Heo3d3c2372011-12-14 00:33:42 +010092
93 /* managed by elevator core */
94 char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */
Tejun Heo22f746e2011-12-14 00:33:41 +010095 struct list_head list;
Linus Torvalds1da177e2005-04-16 15:20:36 -070096};
97
98/*
Adrian Bunk54069582006-01-10 00:09:36 +010099 * each queue has an elevator_queue associated with it
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 */
101struct elevator_queue
102{
Tejun Heo22f746e2011-12-14 00:33:41 +0100103 struct elevator_type *type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 void *elevator_data;
105 struct kobject kobj;
Al Viro3d1ab402006-03-18 18:35:43 -0500106 struct mutex sysfs_lock;
Jens Axboe98170642006-07-28 09:23:08 +0200107 struct hlist_head *hash;
Jens Axboe430c62f2010-10-07 09:35:16 +0200108 unsigned int registered:1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109};
110
111/*
112 * block elevator interface
113 */
Jens Axboe165125e2007-07-24 09:28:11 +0200114extern void elv_dispatch_sort(struct request_queue *, struct request *);
115extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
Jens Axboe7eaceac2011-03-10 08:52:07 +0100116extern void elv_add_request(struct request_queue *, struct request *, int);
117extern void __elv_add_request(struct request_queue *, struct request *, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200118extern int elv_merge(struct request_queue *, struct request **, struct bio *);
119extern void elv_merge_requests(struct request_queue *, struct request *,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200121extern void elv_merged_request(struct request_queue *, struct request *, int);
Divyesh Shah812d4022010-04-08 21:14:23 -0700122extern void elv_bio_merged(struct request_queue *q, struct request *,
123 struct bio *);
Jens Axboe165125e2007-07-24 09:28:11 +0200124extern void elv_requeue_request(struct request_queue *, struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200125extern struct request *elv_former_request(struct request_queue *, struct request *);
126extern struct request *elv_latter_request(struct request_queue *, struct request *);
127extern int elv_register_queue(struct request_queue *q);
128extern void elv_unregister_queue(struct request_queue *q);
129extern int elv_may_queue(struct request_queue *, int);
Mike Anderson11914a52008-09-13 20:31:27 +0200130extern void elv_abort_queue(struct request_queue *);
Jens Axboe165125e2007-07-24 09:28:11 +0200131extern void elv_completed_request(struct request_queue *, struct request *);
132extern int elv_set_request(struct request_queue *, struct request *, gfp_t);
133extern void elv_put_request(struct request_queue *, struct request *);
Jerome Marchand26308ea2009-03-27 10:31:51 +0100134extern void elv_drain_elevator(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135
136/*
137 * io scheduler registration
138 */
Tejun Heo3d3c2372011-12-14 00:33:42 +0100139extern int elv_register(struct elevator_type *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140extern void elv_unregister(struct elevator_type *);
141
142/*
143 * io scheduler sysfs switching
144 */
Jens Axboe165125e2007-07-24 09:28:11 +0200145extern ssize_t elv_iosched_show(struct request_queue *, char *);
146extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147
Jens Axboe165125e2007-07-24 09:28:11 +0200148extern int elevator_init(struct request_queue *, char *);
Jens Axboeb374d182008-10-31 10:05:07 +0100149extern void elevator_exit(struct elevator_queue *);
Jens Axboe5dd531a2010-08-23 13:52:19 +0200150extern int elevator_change(struct request_queue *, const char *);
Tejun Heo050c8ea2012-02-08 09:19:38 +0100151extern bool elv_rq_merge_ok(struct request *, struct bio *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152
153/*
Jens Axboe2e662b62006-07-13 11:55:04 +0200154 * Helper functions.
155 */
Jens Axboe165125e2007-07-24 09:28:11 +0200156extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
157extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);
Jens Axboe2e662b62006-07-13 11:55:04 +0200158
159/*
160 * rb support functions.
161 */
Jeff Moyer796d5112011-06-02 21:19:05 +0200162extern void elv_rb_add(struct rb_root *, struct request *);
Jens Axboe2e662b62006-07-13 11:55:04 +0200163extern void elv_rb_del(struct rb_root *, struct request *);
164extern struct request *elv_rb_find(struct rb_root *, sector_t);
165
166/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 * Return values from elevator merger
168 */
169#define ELEVATOR_NO_MERGE 0
170#define ELEVATOR_FRONT_MERGE 1
171#define ELEVATOR_BACK_MERGE 2
172
173/*
174 * Insertion selection
175 */
176#define ELEVATOR_INSERT_FRONT 1
177#define ELEVATOR_INSERT_BACK 2
178#define ELEVATOR_INSERT_SORT 3
Tejun Heo797e7db2006-01-06 09:51:03 +0100179#define ELEVATOR_INSERT_REQUEUE 4
Tejun Heoae1b1532011-01-25 12:43:54 +0100180#define ELEVATOR_INSERT_FLUSH 5
Jens Axboe5e84ea32011-03-21 10:14:27 +0100181#define ELEVATOR_INSERT_SORT_MERGE 6
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182
183/*
184 * return values from elevator_may_queue_fn
185 */
186enum {
187 ELV_MQUEUE_MAY,
188 ELV_MQUEUE_NO,
189 ELV_MQUEUE_MUST,
190};
191
Tejun Heo2e46e8b2009-05-07 22:24:41 +0900192#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
Jens Axboe2e662b62006-07-13 11:55:04 +0200193#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
Jens Axboe1b47f532005-10-20 16:37:00 +0200194
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200195/*
Jens Axboec7c22e42008-09-13 20:26:01 +0200196 * Hack to reuse the csd.list list_head as the fifo time holder while
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200197 * the request is in the io scheduler. Saves an unsigned long in rq.
198 */
Jens Axboec7c22e42008-09-13 20:26:01 +0200199#define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next)
200#define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp))
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200201#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
202#define rq_fifo_clear(rq) do { \
203 list_del_init(&(rq)->queuelist); \
Jens Axboec7c22e42008-09-13 20:26:01 +0200204 INIT_LIST_HEAD(&(rq)->csd.list); \
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200205 } while (0)
206
David Howells93614012006-09-30 20:45:40 +0200207#endif /* CONFIG_BLOCK */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208#endif