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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 | |
165125e1 | 17 | typedef int (elevator_dispatch_fn) (struct request_queue *, int); |
1da177e4 | 18 | |
165125e1 JA |
19 | typedef void (elevator_add_req_fn) (struct request_queue *, struct request *); |
20 | typedef int (elevator_queue_empty_fn) (struct request_queue *); | |
21 | typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *); | |
22 | typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *); | |
23 | typedef int (elevator_may_queue_fn) (struct request_queue *, int); | |
1da177e4 | 24 | |
165125e1 | 25 | typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, gfp_t); |
bb37b94c | 26 | typedef void (elevator_put_req_fn) (struct request *); |
165125e1 JA |
27 | typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *); |
28 | typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *); | |
1da177e4 | 29 | |
165125e1 | 30 | typedef void *(elevator_init_fn) (struct request_queue *); |
b374d18a | 31 | typedef void (elevator_exit_fn) (struct elevator_queue *); |
1da177e4 LT |
32 | |
33 | struct elevator_ops | |
34 | { | |
35 | elevator_merge_fn *elevator_merge_fn; | |
36 | elevator_merged_fn *elevator_merged_fn; | |
37 | elevator_merge_req_fn *elevator_merge_req_fn; | |
da775265 | 38 | elevator_allow_merge_fn *elevator_allow_merge_fn; |
1da177e4 | 39 | |
8922e16c | 40 | elevator_dispatch_fn *elevator_dispatch_fn; |
1da177e4 | 41 | elevator_add_req_fn *elevator_add_req_fn; |
8922e16c | 42 | elevator_activate_req_fn *elevator_activate_req_fn; |
1da177e4 LT |
43 | elevator_deactivate_req_fn *elevator_deactivate_req_fn; |
44 | ||
45 | elevator_queue_empty_fn *elevator_queue_empty_fn; | |
46 | elevator_completed_req_fn *elevator_completed_req_fn; | |
47 | ||
48 | elevator_request_list_fn *elevator_former_req_fn; | |
49 | elevator_request_list_fn *elevator_latter_req_fn; | |
50 | ||
51 | elevator_set_req_fn *elevator_set_req_fn; | |
52 | elevator_put_req_fn *elevator_put_req_fn; | |
53 | ||
54 | elevator_may_queue_fn *elevator_may_queue_fn; | |
55 | ||
56 | elevator_init_fn *elevator_init_fn; | |
57 | elevator_exit_fn *elevator_exit_fn; | |
e17a9489 | 58 | void (*trim)(struct io_context *); |
1da177e4 LT |
59 | }; |
60 | ||
61 | #define ELV_NAME_MAX (16) | |
62 | ||
e572ec7e AV |
63 | struct elv_fs_entry { |
64 | struct attribute attr; | |
b374d18a JA |
65 | ssize_t (*show)(struct elevator_queue *, char *); |
66 | ssize_t (*store)(struct elevator_queue *, const char *, size_t); | |
e572ec7e AV |
67 | }; |
68 | ||
1da177e4 LT |
69 | /* |
70 | * identifies an elevator type, such as AS or deadline | |
71 | */ | |
72 | struct elevator_type | |
73 | { | |
74 | struct list_head list; | |
75 | struct elevator_ops ops; | |
e572ec7e | 76 | struct elv_fs_entry *elevator_attrs; |
1da177e4 LT |
77 | char elevator_name[ELV_NAME_MAX]; |
78 | struct module *elevator_owner; | |
79 | }; | |
80 | ||
81 | /* | |
54069588 | 82 | * each queue has an elevator_queue associated with it |
1da177e4 LT |
83 | */ |
84 | struct elevator_queue | |
85 | { | |
86 | struct elevator_ops *ops; | |
87 | void *elevator_data; | |
88 | struct kobject kobj; | |
89 | struct elevator_type *elevator_type; | |
3d1ab40f | 90 | struct mutex sysfs_lock; |
9817064b | 91 | struct hlist_head *hash; |
1da177e4 LT |
92 | }; |
93 | ||
94 | /* | |
95 | * block elevator interface | |
96 | */ | |
165125e1 JA |
97 | extern void elv_dispatch_sort(struct request_queue *, struct request *); |
98 | extern void elv_dispatch_add_tail(struct request_queue *, struct request *); | |
99 | extern void elv_add_request(struct request_queue *, struct request *, int, int); | |
100 | extern void __elv_add_request(struct request_queue *, struct request *, int, int); | |
101 | extern void elv_insert(struct request_queue *, struct request *, int); | |
102 | extern int elv_merge(struct request_queue *, struct request **, struct bio *); | |
103 | extern void elv_merge_requests(struct request_queue *, struct request *, | |
1da177e4 | 104 | struct request *); |
165125e1 JA |
105 | extern void elv_merged_request(struct request_queue *, struct request *, int); |
106 | extern void elv_dequeue_request(struct request_queue *, struct request *); | |
107 | extern void elv_requeue_request(struct request_queue *, struct request *); | |
108 | extern int elv_queue_empty(struct request_queue *); | |
1da177e4 | 109 | extern struct request *elv_next_request(struct request_queue *q); |
165125e1 JA |
110 | extern struct request *elv_former_request(struct request_queue *, struct request *); |
111 | extern struct request *elv_latter_request(struct request_queue *, struct request *); | |
112 | extern int elv_register_queue(struct request_queue *q); | |
113 | extern void elv_unregister_queue(struct request_queue *q); | |
114 | extern int elv_may_queue(struct request_queue *, int); | |
11914a53 | 115 | extern void elv_abort_queue(struct request_queue *); |
165125e1 JA |
116 | extern void elv_completed_request(struct request_queue *, struct request *); |
117 | extern int elv_set_request(struct request_queue *, struct request *, gfp_t); | |
118 | extern void elv_put_request(struct request_queue *, struct request *); | |
26308eab | 119 | extern void elv_drain_elevator(struct request_queue *); |
1da177e4 LT |
120 | |
121 | /* | |
122 | * io scheduler registration | |
123 | */ | |
2fdd82bd | 124 | extern void elv_register(struct elevator_type *); |
1da177e4 LT |
125 | extern void elv_unregister(struct elevator_type *); |
126 | ||
127 | /* | |
128 | * io scheduler sysfs switching | |
129 | */ | |
165125e1 JA |
130 | extern ssize_t elv_iosched_show(struct request_queue *, char *); |
131 | extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); | |
1da177e4 | 132 | |
165125e1 | 133 | extern int elevator_init(struct request_queue *, char *); |
b374d18a | 134 | extern void elevator_exit(struct elevator_queue *); |
1da177e4 | 135 | extern int elv_rq_merge_ok(struct request *, struct bio *); |
1da177e4 | 136 | |
2e662b65 JA |
137 | /* |
138 | * Helper functions. | |
139 | */ | |
165125e1 JA |
140 | extern struct request *elv_rb_former_request(struct request_queue *, struct request *); |
141 | extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); | |
2e662b65 JA |
142 | |
143 | /* | |
144 | * rb support functions. | |
145 | */ | |
146 | extern struct request *elv_rb_add(struct rb_root *, struct request *); | |
147 | extern void elv_rb_del(struct rb_root *, struct request *); | |
148 | extern struct request *elv_rb_find(struct rb_root *, sector_t); | |
149 | ||
1da177e4 LT |
150 | /* |
151 | * Return values from elevator merger | |
152 | */ | |
153 | #define ELEVATOR_NO_MERGE 0 | |
154 | #define ELEVATOR_FRONT_MERGE 1 | |
155 | #define ELEVATOR_BACK_MERGE 2 | |
156 | ||
157 | /* | |
158 | * Insertion selection | |
159 | */ | |
160 | #define ELEVATOR_INSERT_FRONT 1 | |
161 | #define ELEVATOR_INSERT_BACK 2 | |
162 | #define ELEVATOR_INSERT_SORT 3 | |
797e7dbb | 163 | #define ELEVATOR_INSERT_REQUEUE 4 |
1da177e4 LT |
164 | |
165 | /* | |
166 | * return values from elevator_may_queue_fn | |
167 | */ | |
168 | enum { | |
169 | ELV_MQUEUE_MAY, | |
170 | ELV_MQUEUE_NO, | |
171 | ELV_MQUEUE_MUST, | |
172 | }; | |
173 | ||
1b47f531 | 174 | #define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors) |
2e662b65 | 175 | #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) |
1b47f531 | 176 | |
1fbfdfcd | 177 | /* |
c7c22e4d | 178 | * Hack to reuse the csd.list list_head as the fifo time holder while |
1fbfdfcd JA |
179 | * the request is in the io scheduler. Saves an unsigned long in rq. |
180 | */ | |
c7c22e4d JA |
181 | #define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next) |
182 | #define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp)) | |
1fbfdfcd JA |
183 | #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) |
184 | #define rq_fifo_clear(rq) do { \ | |
185 | list_del_init(&(rq)->queuelist); \ | |
c7c22e4d | 186 | INIT_LIST_HEAD(&(rq)->csd.list); \ |
1fbfdfcd JA |
187 | } while (0) |
188 | ||
4a893e83 JA |
189 | /* |
190 | * io context count accounting | |
191 | */ | |
192 | #define elv_ioc_count_mod(name, __val) \ | |
193 | do { \ | |
194 | preempt_disable(); \ | |
195 | __get_cpu_var(name) += (__val); \ | |
196 | preempt_enable(); \ | |
197 | } while (0) | |
198 | ||
199 | #define elv_ioc_count_inc(name) elv_ioc_count_mod(name, 1) | |
200 | #define elv_ioc_count_dec(name) elv_ioc_count_mod(name, -1) | |
201 | ||
202 | #define elv_ioc_count_read(name) \ | |
203 | ({ \ | |
204 | unsigned long __val = 0; \ | |
205 | int __cpu; \ | |
206 | smp_wmb(); \ | |
207 | for_each_possible_cpu(__cpu) \ | |
208 | __val += per_cpu(name, __cpu); \ | |
209 | __val; \ | |
210 | }) | |
211 | ||
9361401e | 212 | #endif /* CONFIG_BLOCK */ |
1da177e4 | 213 | #endif |