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1da177e4 LT |
1 | #ifndef _LINUX_ELEVATOR_H |
2 | #define _LINUX_ELEVATOR_H | |
3 | ||
4a893e83 JA |
4 | #include <linux/percpu.h> |
5 | ||
9361401e DH |
6 | #ifdef CONFIG_BLOCK |
7 | ||
165125e1 | 8 | typedef int (elevator_merge_fn) (struct request_queue *, struct request **, |
1da177e4 LT |
9 | struct bio *); |
10 | ||
165125e1 | 11 | typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *); |
1da177e4 | 12 | |
165125e1 | 13 | typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int); |
1da177e4 | 14 | |
165125e1 | 15 | typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *); |
da775265 | 16 | |
812d4026 DS |
17 | typedef void (elevator_bio_merged_fn) (struct request_queue *, |
18 | struct request *, struct bio *); | |
19 | ||
165125e1 | 20 | typedef int (elevator_dispatch_fn) (struct request_queue *, int); |
1da177e4 | 21 | |
165125e1 | 22 | typedef void (elevator_add_req_fn) (struct request_queue *, struct request *); |
165125e1 JA |
23 | typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *); |
24 | typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *); | |
25 | typedef int (elevator_may_queue_fn) (struct request_queue *, int); | |
1da177e4 | 26 | |
165125e1 | 27 | typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, gfp_t); |
bb37b94c | 28 | typedef void (elevator_put_req_fn) (struct request *); |
165125e1 JA |
29 | typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *); |
30 | typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *); | |
1da177e4 | 31 | |
165125e1 | 32 | typedef void *(elevator_init_fn) (struct request_queue *); |
b374d18a | 33 | typedef void (elevator_exit_fn) (struct elevator_queue *); |
1da177e4 LT |
34 | |
35 | struct elevator_ops | |
36 | { | |
37 | elevator_merge_fn *elevator_merge_fn; | |
38 | elevator_merged_fn *elevator_merged_fn; | |
39 | elevator_merge_req_fn *elevator_merge_req_fn; | |
da775265 | 40 | elevator_allow_merge_fn *elevator_allow_merge_fn; |
bd87b589 TH |
41 | |
42 | /* | |
43 | * Used for both plugged list and elevator merging and in the | |
44 | * former case called without queue_lock. Read comment on top of | |
45 | * attempt_plug_merge() for details. | |
46 | */ | |
812d4026 | 47 | elevator_bio_merged_fn *elevator_bio_merged_fn; |
1da177e4 | 48 | |
8922e16c | 49 | elevator_dispatch_fn *elevator_dispatch_fn; |
1da177e4 | 50 | elevator_add_req_fn *elevator_add_req_fn; |
8922e16c | 51 | elevator_activate_req_fn *elevator_activate_req_fn; |
1da177e4 LT |
52 | elevator_deactivate_req_fn *elevator_deactivate_req_fn; |
53 | ||
1da177e4 LT |
54 | elevator_completed_req_fn *elevator_completed_req_fn; |
55 | ||
56 | elevator_request_list_fn *elevator_former_req_fn; | |
57 | elevator_request_list_fn *elevator_latter_req_fn; | |
58 | ||
59 | elevator_set_req_fn *elevator_set_req_fn; | |
60 | elevator_put_req_fn *elevator_put_req_fn; | |
61 | ||
62 | elevator_may_queue_fn *elevator_may_queue_fn; | |
63 | ||
64 | elevator_init_fn *elevator_init_fn; | |
65 | elevator_exit_fn *elevator_exit_fn; | |
e17a9489 | 66 | void (*trim)(struct io_context *); |
1da177e4 LT |
67 | }; |
68 | ||
69 | #define ELV_NAME_MAX (16) | |
70 | ||
e572ec7e AV |
71 | struct elv_fs_entry { |
72 | struct attribute attr; | |
b374d18a JA |
73 | ssize_t (*show)(struct elevator_queue *, char *); |
74 | ssize_t (*store)(struct elevator_queue *, const char *, size_t); | |
e572ec7e AV |
75 | }; |
76 | ||
1da177e4 LT |
77 | /* |
78 | * identifies an elevator type, such as AS or deadline | |
79 | */ | |
80 | struct elevator_type | |
81 | { | |
82 | struct list_head list; | |
83 | struct elevator_ops ops; | |
e572ec7e | 84 | struct elv_fs_entry *elevator_attrs; |
1da177e4 LT |
85 | char elevator_name[ELV_NAME_MAX]; |
86 | struct module *elevator_owner; | |
87 | }; | |
88 | ||
89 | /* | |
54069588 | 90 | * each queue has an elevator_queue associated with it |
1da177e4 LT |
91 | */ |
92 | struct elevator_queue | |
93 | { | |
94 | struct elevator_ops *ops; | |
95 | void *elevator_data; | |
96 | struct kobject kobj; | |
97 | struct elevator_type *elevator_type; | |
3d1ab40f | 98 | struct mutex sysfs_lock; |
9817064b | 99 | struct hlist_head *hash; |
430c62fb | 100 | unsigned int registered:1; |
1da177e4 LT |
101 | }; |
102 | ||
103 | /* | |
104 | * block elevator interface | |
105 | */ | |
165125e1 JA |
106 | extern void elv_dispatch_sort(struct request_queue *, struct request *); |
107 | extern void elv_dispatch_add_tail(struct request_queue *, struct request *); | |
7eaceacc JA |
108 | extern void elv_add_request(struct request_queue *, struct request *, int); |
109 | extern void __elv_add_request(struct request_queue *, struct request *, int); | |
165125e1 | 110 | extern int elv_merge(struct request_queue *, struct request **, struct bio *); |
73c10101 | 111 | extern int elv_try_merge(struct request *, struct bio *); |
165125e1 | 112 | extern void elv_merge_requests(struct request_queue *, struct request *, |
1da177e4 | 113 | struct request *); |
165125e1 | 114 | extern void elv_merged_request(struct request_queue *, struct request *, int); |
812d4026 DS |
115 | extern void elv_bio_merged(struct request_queue *q, struct request *, |
116 | struct bio *); | |
165125e1 | 117 | extern void elv_requeue_request(struct request_queue *, struct request *); |
165125e1 JA |
118 | extern struct request *elv_former_request(struct request_queue *, struct request *); |
119 | extern struct request *elv_latter_request(struct request_queue *, struct request *); | |
120 | extern int elv_register_queue(struct request_queue *q); | |
121 | extern void elv_unregister_queue(struct request_queue *q); | |
122 | extern int elv_may_queue(struct request_queue *, int); | |
11914a53 | 123 | extern void elv_abort_queue(struct request_queue *); |
165125e1 JA |
124 | extern void elv_completed_request(struct request_queue *, struct request *); |
125 | extern int elv_set_request(struct request_queue *, struct request *, gfp_t); | |
126 | extern void elv_put_request(struct request_queue *, struct request *); | |
26308eab | 127 | extern void elv_drain_elevator(struct request_queue *); |
1da177e4 LT |
128 | |
129 | /* | |
130 | * io scheduler registration | |
131 | */ | |
2fdd82bd | 132 | extern void elv_register(struct elevator_type *); |
1da177e4 LT |
133 | extern void elv_unregister(struct elevator_type *); |
134 | ||
135 | /* | |
136 | * io scheduler sysfs switching | |
137 | */ | |
165125e1 JA |
138 | extern ssize_t elv_iosched_show(struct request_queue *, char *); |
139 | extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); | |
1da177e4 | 140 | |
165125e1 | 141 | extern int elevator_init(struct request_queue *, char *); |
b374d18a | 142 | extern void elevator_exit(struct elevator_queue *); |
5dd531a0 | 143 | extern int elevator_change(struct request_queue *, const char *); |
1da177e4 | 144 | extern int elv_rq_merge_ok(struct request *, struct bio *); |
1da177e4 | 145 | |
2e662b65 JA |
146 | /* |
147 | * Helper functions. | |
148 | */ | |
165125e1 JA |
149 | extern struct request *elv_rb_former_request(struct request_queue *, struct request *); |
150 | extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); | |
2e662b65 JA |
151 | |
152 | /* | |
153 | * rb support functions. | |
154 | */ | |
796d5116 | 155 | extern void elv_rb_add(struct rb_root *, struct request *); |
2e662b65 JA |
156 | extern void elv_rb_del(struct rb_root *, struct request *); |
157 | extern struct request *elv_rb_find(struct rb_root *, sector_t); | |
158 | ||
1da177e4 LT |
159 | /* |
160 | * Return values from elevator merger | |
161 | */ | |
162 | #define ELEVATOR_NO_MERGE 0 | |
163 | #define ELEVATOR_FRONT_MERGE 1 | |
164 | #define ELEVATOR_BACK_MERGE 2 | |
165 | ||
166 | /* | |
167 | * Insertion selection | |
168 | */ | |
169 | #define ELEVATOR_INSERT_FRONT 1 | |
170 | #define ELEVATOR_INSERT_BACK 2 | |
171 | #define ELEVATOR_INSERT_SORT 3 | |
797e7dbb | 172 | #define ELEVATOR_INSERT_REQUEUE 4 |
ae1b1539 | 173 | #define ELEVATOR_INSERT_FLUSH 5 |
5e84ea3a | 174 | #define ELEVATOR_INSERT_SORT_MERGE 6 |
1da177e4 LT |
175 | |
176 | /* | |
177 | * return values from elevator_may_queue_fn | |
178 | */ | |
179 | enum { | |
180 | ELV_MQUEUE_MAY, | |
181 | ELV_MQUEUE_NO, | |
182 | ELV_MQUEUE_MUST, | |
183 | }; | |
184 | ||
2e46e8b2 | 185 | #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq)) |
2e662b65 | 186 | #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) |
1b47f531 | 187 | |
1fbfdfcd | 188 | /* |
c7c22e4d | 189 | * Hack to reuse the csd.list list_head as the fifo time holder while |
1fbfdfcd JA |
190 | * the request is in the io scheduler. Saves an unsigned long in rq. |
191 | */ | |
c7c22e4d JA |
192 | #define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next) |
193 | #define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp)) | |
1fbfdfcd JA |
194 | #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) |
195 | #define rq_fifo_clear(rq) do { \ | |
196 | list_del_init(&(rq)->queuelist); \ | |
c7c22e4d | 197 | INIT_LIST_HEAD(&(rq)->csd.list); \ |
1fbfdfcd JA |
198 | } while (0) |
199 | ||
4a893e83 JA |
200 | /* |
201 | * io context count accounting | |
202 | */ | |
909ea964 CL |
203 | #define elv_ioc_count_mod(name, __val) this_cpu_add(name, __val) |
204 | #define elv_ioc_count_inc(name) this_cpu_inc(name) | |
205 | #define elv_ioc_count_dec(name) this_cpu_dec(name) | |
4a893e83 JA |
206 | |
207 | #define elv_ioc_count_read(name) \ | |
208 | ({ \ | |
209 | unsigned long __val = 0; \ | |
210 | int __cpu; \ | |
211 | smp_wmb(); \ | |
212 | for_each_possible_cpu(__cpu) \ | |
213 | __val += per_cpu(name, __cpu); \ | |
214 | __val; \ | |
215 | }) | |
216 | ||
9361401e | 217 | #endif /* CONFIG_BLOCK */ |
1da177e4 | 218 | #endif |