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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_ELEVATOR_H
2#define _LINUX_ELEVATOR_H
3
4typedef int (elevator_merge_fn) (request_queue_t *, struct request **,
5 struct bio *);
6
7typedef void (elevator_merge_req_fn) (request_queue_t *, struct request *, struct request *);
8
9typedef void (elevator_merged_fn) (request_queue_t *, struct request *);
10
Tejun Heo8922e162005-10-20 16:23:44 +020011typedef int (elevator_dispatch_fn) (request_queue_t *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070012
Tejun Heo8922e162005-10-20 16:23:44 +020013typedef void (elevator_add_req_fn) (request_queue_t *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070014typedef int (elevator_queue_empty_fn) (request_queue_t *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070015typedef struct request *(elevator_request_list_fn) (request_queue_t *, struct request *);
16typedef void (elevator_completed_req_fn) (request_queue_t *, struct request *);
Jens Axboe22e2c502005-06-27 10:55:12 +020017typedef int (elevator_may_queue_fn) (request_queue_t *, int, struct bio *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
Jens Axboe22e2c502005-06-27 10:55:12 +020019typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, struct bio *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070020typedef void (elevator_put_req_fn) (request_queue_t *, struct request *);
Tejun Heo8922e162005-10-20 16:23:44 +020021typedef void (elevator_activate_req_fn) (request_queue_t *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070022typedef void (elevator_deactivate_req_fn) (request_queue_t *, struct request *);
23
24typedef int (elevator_init_fn) (request_queue_t *, elevator_t *);
25typedef void (elevator_exit_fn) (elevator_t *);
26
27struct elevator_ops
28{
29 elevator_merge_fn *elevator_merge_fn;
30 elevator_merged_fn *elevator_merged_fn;
31 elevator_merge_req_fn *elevator_merge_req_fn;
32
Tejun Heo8922e162005-10-20 16:23:44 +020033 elevator_dispatch_fn *elevator_dispatch_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 elevator_add_req_fn *elevator_add_req_fn;
Tejun Heo8922e162005-10-20 16:23:44 +020035 elevator_activate_req_fn *elevator_activate_req_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 elevator_deactivate_req_fn *elevator_deactivate_req_fn;
37
38 elevator_queue_empty_fn *elevator_queue_empty_fn;
39 elevator_completed_req_fn *elevator_completed_req_fn;
40
41 elevator_request_list_fn *elevator_former_req_fn;
42 elevator_request_list_fn *elevator_latter_req_fn;
43
44 elevator_set_req_fn *elevator_set_req_fn;
45 elevator_put_req_fn *elevator_put_req_fn;
46
47 elevator_may_queue_fn *elevator_may_queue_fn;
48
49 elevator_init_fn *elevator_init_fn;
50 elevator_exit_fn *elevator_exit_fn;
51};
52
53#define ELV_NAME_MAX (16)
54
55/*
56 * identifies an elevator type, such as AS or deadline
57 */
58struct elevator_type
59{
60 struct list_head list;
61 struct elevator_ops ops;
62 struct elevator_type *elevator_type;
63 struct kobj_type *elevator_ktype;
64 char elevator_name[ELV_NAME_MAX];
65 struct module *elevator_owner;
66};
67
68/*
69 * each queue has an elevator_queue assoicated with it
70 */
71struct elevator_queue
72{
73 struct elevator_ops *ops;
74 void *elevator_data;
75 struct kobject kobj;
76 struct elevator_type *elevator_type;
77};
78
79/*
80 * block elevator interface
81 */
Jens Axboe1b47f532005-10-20 16:37:00 +020082extern void elv_dispatch_sort(request_queue_t *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083extern void elv_add_request(request_queue_t *, struct request *, int, int);
84extern void __elv_add_request(request_queue_t *, struct request *, int, int);
85extern int elv_merge(request_queue_t *, struct request **, struct bio *);
86extern void elv_merge_requests(request_queue_t *, struct request *,
87 struct request *);
88extern void elv_merged_request(request_queue_t *, struct request *);
Tejun Heo8922e162005-10-20 16:23:44 +020089extern void elv_dequeue_request(request_queue_t *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090extern void elv_requeue_request(request_queue_t *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070091extern int elv_queue_empty(request_queue_t *);
92extern struct request *elv_next_request(struct request_queue *q);
93extern struct request *elv_former_request(request_queue_t *, struct request *);
94extern struct request *elv_latter_request(request_queue_t *, struct request *);
95extern int elv_register_queue(request_queue_t *q);
96extern void elv_unregister_queue(request_queue_t *q);
Jens Axboe22e2c502005-06-27 10:55:12 +020097extern int elv_may_queue(request_queue_t *, int, struct bio *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070098extern void elv_completed_request(request_queue_t *, struct request *);
Jens Axboe22e2c502005-06-27 10:55:12 +020099extern int elv_set_request(request_queue_t *, struct request *, struct bio *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100extern void elv_put_request(request_queue_t *, struct request *);
101
102/*
103 * io scheduler registration
104 */
105extern int elv_register(struct elevator_type *);
106extern void elv_unregister(struct elevator_type *);
107
108/*
109 * io scheduler sysfs switching
110 */
111extern ssize_t elv_iosched_show(request_queue_t *, char *);
112extern ssize_t elv_iosched_store(request_queue_t *, const char *, size_t);
113
114extern int elevator_init(request_queue_t *, char *);
115extern void elevator_exit(elevator_t *);
116extern int elv_rq_merge_ok(struct request *, struct bio *);
117extern int elv_try_merge(struct request *, struct bio *);
118extern int elv_try_last_merge(request_queue_t *, struct bio *);
119
120/*
121 * Return values from elevator merger
122 */
123#define ELEVATOR_NO_MERGE 0
124#define ELEVATOR_FRONT_MERGE 1
125#define ELEVATOR_BACK_MERGE 2
126
127/*
128 * Insertion selection
129 */
130#define ELEVATOR_INSERT_FRONT 1
131#define ELEVATOR_INSERT_BACK 2
132#define ELEVATOR_INSERT_SORT 3
133
134/*
135 * return values from elevator_may_queue_fn
136 */
137enum {
138 ELV_MQUEUE_MAY,
139 ELV_MQUEUE_NO,
140 ELV_MQUEUE_MUST,
141};
142
Jens Axboe1b47f532005-10-20 16:37:00 +0200143#define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors)
144
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145#endif