1 #ifndef _LINUX_ELEVATOR_H
2 #define _LINUX_ELEVATOR_H
4 typedef int (elevator_merge_fn
) (request_queue_t
*, struct request
**,
7 typedef void (elevator_merge_req_fn
) (request_queue_t
*, struct request
*, struct request
*);
9 typedef void (elevator_merged_fn
) (request_queue_t
*, struct request
*);
11 typedef int (elevator_dispatch_fn
) (request_queue_t
*, int);
13 typedef void (elevator_add_req_fn
) (request_queue_t
*, struct request
*);
14 typedef int (elevator_queue_empty_fn
) (request_queue_t
*);
15 typedef struct request
*(elevator_request_list_fn
) (request_queue_t
*, struct request
*);
16 typedef void (elevator_completed_req_fn
) (request_queue_t
*, struct request
*);
17 typedef int (elevator_may_queue_fn
) (request_queue_t
*, int, struct bio
*);
19 typedef int (elevator_set_req_fn
) (request_queue_t
*, struct request
*, struct bio
*, gfp_t
);
20 typedef void (elevator_put_req_fn
) (request_queue_t
*, struct request
*);
21 typedef void (elevator_activate_req_fn
) (request_queue_t
*, struct request
*);
22 typedef void (elevator_deactivate_req_fn
) (request_queue_t
*, struct request
*);
24 typedef int (elevator_init_fn
) (request_queue_t
*, elevator_t
*);
25 typedef void (elevator_exit_fn
) (elevator_t
*);
29 elevator_merge_fn
*elevator_merge_fn
;
30 elevator_merged_fn
*elevator_merged_fn
;
31 elevator_merge_req_fn
*elevator_merge_req_fn
;
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
;
38 elevator_queue_empty_fn
*elevator_queue_empty_fn
;
39 elevator_completed_req_fn
*elevator_completed_req_fn
;
41 elevator_request_list_fn
*elevator_former_req_fn
;
42 elevator_request_list_fn
*elevator_latter_req_fn
;
44 elevator_set_req_fn
*elevator_set_req_fn
;
45 elevator_put_req_fn
*elevator_put_req_fn
;
47 elevator_may_queue_fn
*elevator_may_queue_fn
;
49 elevator_init_fn
*elevator_init_fn
;
50 elevator_exit_fn
*elevator_exit_fn
;
53 #define ELV_NAME_MAX (16)
56 * identifies an elevator type, such as AS or deadline
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
;
69 * each queue has an elevator_queue assoicated with it
73 struct elevator_ops
*ops
;
76 struct elevator_type
*elevator_type
;
80 * block elevator interface
82 extern void elv_dispatch_sort(request_queue_t
*, struct request
*);
83 extern void elv_add_request(request_queue_t
*, struct request
*, int, int);
84 extern void __elv_add_request(request_queue_t
*, struct request
*, int, int);
85 extern int elv_merge(request_queue_t
*, struct request
**, struct bio
*);
86 extern void elv_merge_requests(request_queue_t
*, struct request
*,
88 extern void elv_merged_request(request_queue_t
*, struct request
*);
89 extern void elv_dequeue_request(request_queue_t
*, struct request
*);
90 extern void elv_requeue_request(request_queue_t
*, struct request
*);
91 extern int elv_queue_empty(request_queue_t
*);
92 extern struct request
*elv_next_request(struct request_queue
*q
);
93 extern struct request
*elv_former_request(request_queue_t
*, struct request
*);
94 extern struct request
*elv_latter_request(request_queue_t
*, struct request
*);
95 extern int elv_register_queue(request_queue_t
*q
);
96 extern void elv_unregister_queue(request_queue_t
*q
);
97 extern int elv_may_queue(request_queue_t
*, int, struct bio
*);
98 extern void elv_completed_request(request_queue_t
*, struct request
*);
99 extern int elv_set_request(request_queue_t
*, struct request
*, struct bio
*, gfp_t
);
100 extern void elv_put_request(request_queue_t
*, struct request
*);
103 * io scheduler registration
105 extern int elv_register(struct elevator_type
*);
106 extern void elv_unregister(struct elevator_type
*);
109 * io scheduler sysfs switching
111 extern ssize_t
elv_iosched_show(request_queue_t
*, char *);
112 extern ssize_t
elv_iosched_store(request_queue_t
*, const char *, size_t);
114 extern int elevator_init(request_queue_t
*, char *);
115 extern void elevator_exit(elevator_t
*);
116 extern int elv_rq_merge_ok(struct request
*, struct bio
*);
117 extern int elv_try_merge(struct request
*, struct bio
*);
118 extern int elv_try_last_merge(request_queue_t
*, struct bio
*);
121 * Return values from elevator merger
123 #define ELEVATOR_NO_MERGE 0
124 #define ELEVATOR_FRONT_MERGE 1
125 #define ELEVATOR_BACK_MERGE 2
128 * Insertion selection
130 #define ELEVATOR_INSERT_FRONT 1
131 #define ELEVATOR_INSERT_BACK 2
132 #define ELEVATOR_INSERT_SORT 3
133 #define ELEVATOR_INSERT_REQUEUE 4
136 * return values from elevator_may_queue_fn
144 #define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors)