Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1#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
11typedef int (elevator_dispatch_fn) (request_queue_t *, int);
12
13typedef void (elevator_add_req_fn) (request_queue_t *, struct request *);
14typedef int (elevator_queue_empty_fn) (request_queue_t *);
15typedef struct request *(elevator_request_list_fn) (request_queue_t *, struct request *);
16typedef void (elevator_completed_req_fn) (request_queue_t *, struct request *);
17typedef int (elevator_may_queue_fn) (request_queue_t *, int, struct bio *);
18
19typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, struct bio *, gfp_t);
20typedef void (elevator_put_req_fn) (request_queue_t *, struct request *);
21typedef void (elevator_activate_req_fn) (request_queue_t *, struct request *);
22typedef 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
33 elevator_dispatch_fn *elevator_dispatch_fn;
34 elevator_add_req_fn *elevator_add_req_fn;
35 elevator_activate_req_fn *elevator_activate_req_fn;
36 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 associated 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 */
82extern void elv_dispatch_sort(request_queue_t *, struct request *);
83extern void elv_add_request(request_queue_t *, struct request *, int, int);
84extern void __elv_add_request(request_queue_t *, struct request *, int, int);
85extern void elv_insert(request_queue_t *, struct request *, int);
86extern int elv_merge(request_queue_t *, struct request **, struct bio *);
87extern void elv_merge_requests(request_queue_t *, struct request *,
88 struct request *);
89extern void elv_merged_request(request_queue_t *, struct request *);
90extern void elv_dequeue_request(request_queue_t *, struct request *);
91extern void elv_requeue_request(request_queue_t *, struct request *);
92extern int elv_queue_empty(request_queue_t *);
93extern struct request *elv_next_request(struct request_queue *q);
94extern struct request *elv_former_request(request_queue_t *, struct request *);
95extern struct request *elv_latter_request(request_queue_t *, struct request *);
96extern int elv_register_queue(request_queue_t *q);
97extern void elv_unregister_queue(request_queue_t *q);
98extern int elv_may_queue(request_queue_t *, int, struct bio *);
99extern void elv_completed_request(request_queue_t *, struct request *);
100extern int elv_set_request(request_queue_t *, struct request *, struct bio *, gfp_t);
101extern void elv_put_request(request_queue_t *, struct request *);
102
103/*
104 * io scheduler registration
105 */
106extern int elv_register(struct elevator_type *);
107extern void elv_unregister(struct elevator_type *);
108
109/*
110 * io scheduler sysfs switching
111 */
112extern ssize_t elv_iosched_show(request_queue_t *, char *);
113extern ssize_t elv_iosched_store(request_queue_t *, const char *, size_t);
114
115extern int elevator_init(request_queue_t *, char *);
116extern void elevator_exit(elevator_t *);
117extern int elv_rq_merge_ok(struct request *, struct bio *);
118
119/*
120 * Return values from elevator merger
121 */
122#define ELEVATOR_NO_MERGE 0
123#define ELEVATOR_FRONT_MERGE 1
124#define ELEVATOR_BACK_MERGE 2
125
126/*
127 * Insertion selection
128 */
129#define ELEVATOR_INSERT_FRONT 1
130#define ELEVATOR_INSERT_BACK 2
131#define ELEVATOR_INSERT_SORT 3
132#define ELEVATOR_INSERT_REQUEUE 4
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
143#define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors)
144
145#endif