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1da177e4 LT |
1 | #ifndef _LINUX_ELEVATOR_H |
2 | #define _LINUX_ELEVATOR_H | |
3 | ||
4 | typedef int (elevator_merge_fn) (request_queue_t *, struct request **, | |
5 | struct bio *); | |
6 | ||
7 | typedef void (elevator_merge_req_fn) (request_queue_t *, struct request *, struct request *); | |
8 | ||
2e662b65 | 9 | typedef void (elevator_merged_fn) (request_queue_t *, struct request *, int); |
1da177e4 | 10 | |
8922e16c | 11 | typedef int (elevator_dispatch_fn) (request_queue_t *, int); |
1da177e4 | 12 | |
8922e16c | 13 | typedef void (elevator_add_req_fn) (request_queue_t *, struct request *); |
1da177e4 | 14 | typedef int (elevator_queue_empty_fn) (request_queue_t *); |
1da177e4 LT |
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 *); | |
22e2c507 | 17 | typedef int (elevator_may_queue_fn) (request_queue_t *, int, struct bio *); |
1da177e4 | 18 | |
8267e268 | 19 | typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, struct bio *, gfp_t); |
1da177e4 | 20 | typedef void (elevator_put_req_fn) (request_queue_t *, struct request *); |
8922e16c | 21 | typedef void (elevator_activate_req_fn) (request_queue_t *, struct request *); |
1da177e4 LT |
22 | typedef void (elevator_deactivate_req_fn) (request_queue_t *, struct request *); |
23 | ||
bc1c1169 | 24 | typedef void *(elevator_init_fn) (request_queue_t *, elevator_t *); |
1da177e4 LT |
25 | typedef void (elevator_exit_fn) (elevator_t *); |
26 | ||
27 | struct 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 | ||
8922e16c | 33 | elevator_dispatch_fn *elevator_dispatch_fn; |
1da177e4 | 34 | elevator_add_req_fn *elevator_add_req_fn; |
8922e16c | 35 | elevator_activate_req_fn *elevator_activate_req_fn; |
1da177e4 LT |
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; | |
e17a9489 | 51 | void (*trim)(struct io_context *); |
1da177e4 LT |
52 | }; |
53 | ||
54 | #define ELV_NAME_MAX (16) | |
55 | ||
e572ec7e AV |
56 | struct 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 | ||
1da177e4 LT |
62 | /* |
63 | * identifies an elevator type, such as AS or deadline | |
64 | */ | |
65 | struct elevator_type | |
66 | { | |
67 | struct list_head list; | |
68 | struct elevator_ops ops; | |
69 | struct elevator_type *elevator_type; | |
e572ec7e | 70 | struct elv_fs_entry *elevator_attrs; |
1da177e4 LT |
71 | char elevator_name[ELV_NAME_MAX]; |
72 | struct module *elevator_owner; | |
73 | }; | |
74 | ||
75 | /* | |
54069588 | 76 | * each queue has an elevator_queue associated with it |
1da177e4 LT |
77 | */ |
78 | struct elevator_queue | |
79 | { | |
80 | struct elevator_ops *ops; | |
81 | void *elevator_data; | |
82 | struct kobject kobj; | |
83 | struct elevator_type *elevator_type; | |
3d1ab40f | 84 | struct mutex sysfs_lock; |
9817064b | 85 | struct hlist_head *hash; |
1da177e4 LT |
86 | }; |
87 | ||
88 | /* | |
89 | * block elevator interface | |
90 | */ | |
1b47f531 | 91 | extern void elv_dispatch_sort(request_queue_t *, struct request *); |
9817064b | 92 | extern void elv_dispatch_add_tail(request_queue_t *, struct request *); |
1da177e4 LT |
93 | extern void elv_add_request(request_queue_t *, struct request *, int, int); |
94 | extern void __elv_add_request(request_queue_t *, struct request *, int, int); | |
30e9656c | 95 | extern void elv_insert(request_queue_t *, struct request *, int); |
1da177e4 LT |
96 | extern int elv_merge(request_queue_t *, struct request **, struct bio *); |
97 | extern void elv_merge_requests(request_queue_t *, struct request *, | |
98 | struct request *); | |
2e662b65 | 99 | extern void elv_merged_request(request_queue_t *, struct request *, int); |
8922e16c | 100 | extern void elv_dequeue_request(request_queue_t *, struct request *); |
1da177e4 | 101 | extern void elv_requeue_request(request_queue_t *, struct request *); |
1da177e4 LT |
102 | extern int elv_queue_empty(request_queue_t *); |
103 | extern struct request *elv_next_request(struct request_queue *q); | |
104 | extern struct request *elv_former_request(request_queue_t *, struct request *); | |
105 | extern struct request *elv_latter_request(request_queue_t *, struct request *); | |
106 | extern int elv_register_queue(request_queue_t *q); | |
107 | extern void elv_unregister_queue(request_queue_t *q); | |
22e2c507 | 108 | extern int elv_may_queue(request_queue_t *, int, struct bio *); |
1da177e4 | 109 | extern void elv_completed_request(request_queue_t *, struct request *); |
8267e268 | 110 | extern int elv_set_request(request_queue_t *, struct request *, struct bio *, gfp_t); |
1da177e4 LT |
111 | extern void elv_put_request(request_queue_t *, struct request *); |
112 | ||
113 | /* | |
114 | * io scheduler registration | |
115 | */ | |
116 | extern int elv_register(struct elevator_type *); | |
117 | extern void elv_unregister(struct elevator_type *); | |
118 | ||
119 | /* | |
120 | * io scheduler sysfs switching | |
121 | */ | |
122 | extern ssize_t elv_iosched_show(request_queue_t *, char *); | |
123 | extern ssize_t elv_iosched_store(request_queue_t *, const char *, size_t); | |
124 | ||
125 | extern int elevator_init(request_queue_t *, char *); | |
126 | extern void elevator_exit(elevator_t *); | |
127 | extern int elv_rq_merge_ok(struct request *, struct bio *); | |
1da177e4 | 128 | |
2e662b65 JA |
129 | /* |
130 | * Helper functions. | |
131 | */ | |
132 | extern struct request *elv_rb_former_request(request_queue_t *, struct request *); | |
133 | extern struct request *elv_rb_latter_request(request_queue_t *, struct request *); | |
134 | ||
135 | /* | |
136 | * rb support functions. | |
137 | */ | |
138 | extern struct request *elv_rb_add(struct rb_root *, struct request *); | |
139 | extern void elv_rb_del(struct rb_root *, struct request *); | |
140 | extern struct request *elv_rb_find(struct rb_root *, sector_t); | |
141 | ||
1da177e4 LT |
142 | /* |
143 | * Return values from elevator merger | |
144 | */ | |
145 | #define ELEVATOR_NO_MERGE 0 | |
146 | #define ELEVATOR_FRONT_MERGE 1 | |
147 | #define ELEVATOR_BACK_MERGE 2 | |
148 | ||
149 | /* | |
150 | * Insertion selection | |
151 | */ | |
152 | #define ELEVATOR_INSERT_FRONT 1 | |
153 | #define ELEVATOR_INSERT_BACK 2 | |
154 | #define ELEVATOR_INSERT_SORT 3 | |
797e7dbb | 155 | #define ELEVATOR_INSERT_REQUEUE 4 |
1da177e4 LT |
156 | |
157 | /* | |
158 | * return values from elevator_may_queue_fn | |
159 | */ | |
160 | enum { | |
161 | ELV_MQUEUE_MAY, | |
162 | ELV_MQUEUE_NO, | |
163 | ELV_MQUEUE_MUST, | |
164 | }; | |
165 | ||
1b47f531 | 166 | #define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors) |
2e662b65 | 167 | #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) |
1b47f531 | 168 | |
1fbfdfcd JA |
169 | /* |
170 | * Hack to reuse the donelist list_head as the fifo time holder while | |
171 | * the request is in the io scheduler. Saves an unsigned long in rq. | |
172 | */ | |
173 | #define rq_fifo_time(rq) ((unsigned long) (rq)->donelist.next) | |
174 | #define rq_set_fifo_time(rq,exp) ((rq)->donelist.next = (void *) (exp)) | |
175 | #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) | |
176 | #define rq_fifo_clear(rq) do { \ | |
177 | list_del_init(&(rq)->queuelist); \ | |
178 | INIT_LIST_HEAD(&(rq)->donelist); \ | |
179 | } while (0) | |
180 | ||
1da177e4 | 181 | #endif |