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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
Al Viro8267e262005-10-21 03:20:53 -040019typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, struct bio *, gfp_t);
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
Jens Axboebc1c1162006-06-08 08:49:06 +020024typedef void *(elevator_init_fn) (request_queue_t *, elevator_t *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070025typedef 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;
Al Viroe17a9482006-03-18 13:21:20 -050051 void (*trim)(struct io_context *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070052};
53
54#define ELV_NAME_MAX (16)
55
Al Viroe572ec72006-03-18 22:27:18 -050056struct elv_fs_entry {
57 struct attribute attr;
58 ssize_t (*show)(elevator_t *, char *);
59 ssize_t (*store)(elevator_t *, const char *, size_t);
60};
61
Linus Torvalds1da177e2005-04-16 15:20:36 -070062/*
63 * identifies an elevator type, such as AS or deadline
64 */
65struct elevator_type
66{
67 struct list_head list;
68 struct elevator_ops ops;
69 struct elevator_type *elevator_type;
Al Viroe572ec72006-03-18 22:27:18 -050070 struct elv_fs_entry *elevator_attrs;
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 char elevator_name[ELV_NAME_MAX];
72 struct module *elevator_owner;
73};
74
75/*
Adrian Bunk54069582006-01-10 00:09:36 +010076 * each queue has an elevator_queue associated with it
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 */
78struct elevator_queue
79{
80 struct elevator_ops *ops;
81 void *elevator_data;
82 struct kobject kobj;
83 struct elevator_type *elevator_type;
Al Viro3d1ab402006-03-18 18:35:43 -050084 struct mutex sysfs_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -070085};
86
87/*
88 * block elevator interface
89 */
Jens Axboe1b47f532005-10-20 16:37:00 +020090extern void elv_dispatch_sort(request_queue_t *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070091extern void elv_add_request(request_queue_t *, struct request *, int, int);
92extern void __elv_add_request(request_queue_t *, struct request *, int, int);
Tejun Heo30e96562006-02-08 01:01:31 -080093extern void elv_insert(request_queue_t *, struct request *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094extern int elv_merge(request_queue_t *, struct request **, struct bio *);
95extern void elv_merge_requests(request_queue_t *, struct request *,
96 struct request *);
97extern void elv_merged_request(request_queue_t *, struct request *);
Tejun Heo8922e162005-10-20 16:23:44 +020098extern void elv_dequeue_request(request_queue_t *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070099extern void elv_requeue_request(request_queue_t *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100extern int elv_queue_empty(request_queue_t *);
101extern struct request *elv_next_request(struct request_queue *q);
102extern struct request *elv_former_request(request_queue_t *, struct request *);
103extern struct request *elv_latter_request(request_queue_t *, struct request *);
104extern int elv_register_queue(request_queue_t *q);
105extern void elv_unregister_queue(request_queue_t *q);
Jens Axboe22e2c502005-06-27 10:55:12 +0200106extern int elv_may_queue(request_queue_t *, int, struct bio *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107extern void elv_completed_request(request_queue_t *, struct request *);
Al Viro8267e262005-10-21 03:20:53 -0400108extern int elv_set_request(request_queue_t *, struct request *, struct bio *, gfp_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109extern void elv_put_request(request_queue_t *, struct request *);
110
111/*
112 * io scheduler registration
113 */
114extern int elv_register(struct elevator_type *);
115extern void elv_unregister(struct elevator_type *);
116
117/*
118 * io scheduler sysfs switching
119 */
120extern ssize_t elv_iosched_show(request_queue_t *, char *);
121extern ssize_t elv_iosched_store(request_queue_t *, const char *, size_t);
122
123extern int elevator_init(request_queue_t *, char *);
124extern void elevator_exit(elevator_t *);
125extern int elv_rq_merge_ok(struct request *, struct bio *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126
127/*
128 * Return values from elevator merger
129 */
130#define ELEVATOR_NO_MERGE 0
131#define ELEVATOR_FRONT_MERGE 1
132#define ELEVATOR_BACK_MERGE 2
133
134/*
135 * Insertion selection
136 */
137#define ELEVATOR_INSERT_FRONT 1
138#define ELEVATOR_INSERT_BACK 2
139#define ELEVATOR_INSERT_SORT 3
Tejun Heo797e7db2006-01-06 09:51:03 +0100140#define ELEVATOR_INSERT_REQUEUE 4
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
142/*
143 * return values from elevator_may_queue_fn
144 */
145enum {
146 ELV_MQUEUE_MAY,
147 ELV_MQUEUE_NO,
148 ELV_MQUEUE_MUST,
149};
150
Jens Axboe1b47f532005-10-20 16:37:00 +0200151#define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors)
152
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153#endif