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1 | #ifndef _LINUX_ELEVATOR_H | |
2 | #define _LINUX_ELEVATOR_H | |
3 | ||
4 | #include <linux/percpu.h> | |
5 | ||
6 | #ifdef CONFIG_BLOCK | |
7 | ||
8 | struct io_cq; | |
9 | ||
10 | typedef int (elevator_merge_fn) (struct request_queue *, struct request **, | |
11 | struct bio *); | |
12 | ||
13 | typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *); | |
14 | ||
15 | typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int); | |
16 | ||
17 | typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *); | |
18 | ||
19 | typedef void (elevator_bio_merged_fn) (struct request_queue *, | |
20 | struct request *, struct bio *); | |
21 | ||
22 | typedef int (elevator_dispatch_fn) (struct request_queue *, int); | |
23 | ||
24 | typedef void (elevator_add_req_fn) (struct request_queue *, struct request *); | |
25 | typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *); | |
26 | typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *); | |
27 | typedef int (elevator_may_queue_fn) (struct request_queue *, int); | |
28 | ||
29 | typedef void (elevator_init_icq_fn) (struct io_cq *); | |
30 | typedef void (elevator_exit_icq_fn) (struct io_cq *); | |
31 | typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, | |
32 | struct bio *, gfp_t); | |
33 | typedef void (elevator_put_req_fn) (struct request *); | |
34 | typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *); | |
35 | typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *); | |
36 | ||
37 | typedef int (elevator_init_fn) (struct request_queue *); | |
38 | typedef void (elevator_exit_fn) (struct elevator_queue *); | |
39 | ||
40 | struct elevator_ops | |
41 | { | |
42 | elevator_merge_fn *elevator_merge_fn; | |
43 | elevator_merged_fn *elevator_merged_fn; | |
44 | elevator_merge_req_fn *elevator_merge_req_fn; | |
45 | elevator_allow_merge_fn *elevator_allow_merge_fn; | |
46 | elevator_bio_merged_fn *elevator_bio_merged_fn; | |
47 | ||
48 | elevator_dispatch_fn *elevator_dispatch_fn; | |
49 | elevator_add_req_fn *elevator_add_req_fn; | |
50 | elevator_activate_req_fn *elevator_activate_req_fn; | |
51 | elevator_deactivate_req_fn *elevator_deactivate_req_fn; | |
52 | ||
53 | elevator_completed_req_fn *elevator_completed_req_fn; | |
54 | ||
55 | elevator_request_list_fn *elevator_former_req_fn; | |
56 | elevator_request_list_fn *elevator_latter_req_fn; | |
57 | ||
58 | elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */ | |
59 | elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */ | |
60 | ||
61 | elevator_set_req_fn *elevator_set_req_fn; | |
62 | elevator_put_req_fn *elevator_put_req_fn; | |
63 | ||
64 | elevator_may_queue_fn *elevator_may_queue_fn; | |
65 | ||
66 | elevator_init_fn *elevator_init_fn; | |
67 | elevator_exit_fn *elevator_exit_fn; | |
68 | }; | |
69 | ||
70 | #define ELV_NAME_MAX (16) | |
71 | ||
72 | struct elv_fs_entry { | |
73 | struct attribute attr; | |
74 | ssize_t (*show)(struct elevator_queue *, char *); | |
75 | ssize_t (*store)(struct elevator_queue *, const char *, size_t); | |
76 | }; | |
77 | ||
78 | /* | |
79 | * identifies an elevator type, such as AS or deadline | |
80 | */ | |
81 | struct elevator_type | |
82 | { | |
83 | /* managed by elevator core */ | |
84 | struct kmem_cache *icq_cache; | |
85 | ||
86 | /* fields provided by elevator implementation */ | |
87 | struct elevator_ops ops; | |
88 | size_t icq_size; /* see iocontext.h */ | |
89 | size_t icq_align; /* ditto */ | |
90 | struct elv_fs_entry *elevator_attrs; | |
91 | char elevator_name[ELV_NAME_MAX]; | |
92 | struct module *elevator_owner; | |
93 | ||
94 | /* managed by elevator core */ | |
95 | char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */ | |
96 | struct list_head list; | |
97 | }; | |
98 | ||
99 | /* | |
100 | * each queue has an elevator_queue associated with it | |
101 | */ | |
102 | struct elevator_queue | |
103 | { | |
104 | struct elevator_type *type; | |
105 | void *elevator_data; | |
106 | struct kobject kobj; | |
107 | struct mutex sysfs_lock; | |
108 | struct hlist_head *hash; | |
109 | unsigned int registered:1; | |
110 | }; | |
111 | ||
112 | /* | |
113 | * block elevator interface | |
114 | */ | |
115 | extern void elv_dispatch_sort(struct request_queue *, struct request *); | |
116 | extern void elv_dispatch_add_tail(struct request_queue *, struct request *); | |
117 | extern void elv_add_request(struct request_queue *, struct request *, int); | |
118 | extern void __elv_add_request(struct request_queue *, struct request *, int); | |
119 | extern int elv_merge(struct request_queue *, struct request **, struct bio *); | |
120 | extern void elv_merge_requests(struct request_queue *, struct request *, | |
121 | struct request *); | |
122 | extern void elv_merged_request(struct request_queue *, struct request *, int); | |
123 | extern void elv_bio_merged(struct request_queue *q, struct request *, | |
124 | struct bio *); | |
125 | extern void elv_requeue_request(struct request_queue *, struct request *); | |
126 | extern struct request *elv_former_request(struct request_queue *, struct request *); | |
127 | extern struct request *elv_latter_request(struct request_queue *, struct request *); | |
128 | extern int elv_register_queue(struct request_queue *q); | |
129 | extern void elv_unregister_queue(struct request_queue *q); | |
130 | extern int elv_may_queue(struct request_queue *, int); | |
131 | extern void elv_abort_queue(struct request_queue *); | |
132 | extern void elv_completed_request(struct request_queue *, struct request *); | |
133 | extern int elv_set_request(struct request_queue *q, struct request *rq, | |
134 | struct bio *bio, gfp_t gfp_mask); | |
135 | extern void elv_put_request(struct request_queue *, struct request *); | |
136 | extern void elv_drain_elevator(struct request_queue *); | |
137 | ||
138 | /* | |
139 | * io scheduler registration | |
140 | */ | |
141 | extern int elv_register(struct elevator_type *); | |
142 | extern void elv_unregister(struct elevator_type *); | |
143 | ||
144 | /* | |
145 | * io scheduler sysfs switching | |
146 | */ | |
147 | extern ssize_t elv_iosched_show(struct request_queue *, char *); | |
148 | extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); | |
149 | ||
150 | extern int elevator_init(struct request_queue *, char *); | |
151 | extern void elevator_exit(struct elevator_queue *); | |
152 | extern int elevator_change(struct request_queue *, const char *); | |
153 | extern bool elv_rq_merge_ok(struct request *, struct bio *); | |
154 | ||
155 | /* | |
156 | * Helper functions. | |
157 | */ | |
158 | extern struct request *elv_rb_former_request(struct request_queue *, struct request *); | |
159 | extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); | |
160 | ||
161 | /* | |
162 | * rb support functions. | |
163 | */ | |
164 | extern void elv_rb_add(struct rb_root *, struct request *); | |
165 | extern void elv_rb_del(struct rb_root *, struct request *); | |
166 | extern struct request *elv_rb_find(struct rb_root *, sector_t); | |
167 | ||
168 | /* | |
169 | * Return values from elevator merger | |
170 | */ | |
171 | #define ELEVATOR_NO_MERGE 0 | |
172 | #define ELEVATOR_FRONT_MERGE 1 | |
173 | #define ELEVATOR_BACK_MERGE 2 | |
174 | ||
175 | /* | |
176 | * Insertion selection | |
177 | */ | |
178 | #define ELEVATOR_INSERT_FRONT 1 | |
179 | #define ELEVATOR_INSERT_BACK 2 | |
180 | #define ELEVATOR_INSERT_SORT 3 | |
181 | #define ELEVATOR_INSERT_REQUEUE 4 | |
182 | #define ELEVATOR_INSERT_FLUSH 5 | |
183 | #define ELEVATOR_INSERT_SORT_MERGE 6 | |
184 | ||
185 | /* | |
186 | * return values from elevator_may_queue_fn | |
187 | */ | |
188 | enum { | |
189 | ELV_MQUEUE_MAY, | |
190 | ELV_MQUEUE_NO, | |
191 | ELV_MQUEUE_MUST, | |
192 | }; | |
193 | ||
194 | #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq)) | |
195 | #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) | |
196 | ||
197 | /* | |
198 | * Hack to reuse the csd.list list_head as the fifo time holder while | |
199 | * the request is in the io scheduler. Saves an unsigned long in rq. | |
200 | */ | |
201 | #define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next) | |
202 | #define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp)) | |
203 | #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) | |
204 | #define rq_fifo_clear(rq) do { \ | |
205 | list_del_init(&(rq)->queuelist); \ | |
206 | INIT_LIST_HEAD(&(rq)->csd.list); \ | |
207 | } while (0) | |
208 | ||
209 | #endif /* CONFIG_BLOCK */ | |
210 | #endif |