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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 | ||
1da177e4 LT |
8 | typedef int (elevator_merge_fn) (request_queue_t *, struct request **, |
9 | struct bio *); | |
10 | ||
11 | typedef void (elevator_merge_req_fn) (request_queue_t *, struct request *, struct request *); | |
12 | ||
2e662b65 | 13 | typedef void (elevator_merged_fn) (request_queue_t *, struct request *, int); |
1da177e4 | 14 | |
8922e16c | 15 | typedef int (elevator_dispatch_fn) (request_queue_t *, int); |
1da177e4 | 16 | |
8922e16c | 17 | typedef void (elevator_add_req_fn) (request_queue_t *, struct request *); |
1da177e4 | 18 | typedef int (elevator_queue_empty_fn) (request_queue_t *); |
1da177e4 LT |
19 | typedef struct request *(elevator_request_list_fn) (request_queue_t *, struct request *); |
20 | typedef void (elevator_completed_req_fn) (request_queue_t *, struct request *); | |
cb78b285 | 21 | typedef int (elevator_may_queue_fn) (request_queue_t *, int); |
1da177e4 | 22 | |
cb78b285 | 23 | typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, gfp_t); |
1da177e4 | 24 | typedef void (elevator_put_req_fn) (request_queue_t *, struct request *); |
8922e16c | 25 | typedef void (elevator_activate_req_fn) (request_queue_t *, struct request *); |
1da177e4 LT |
26 | typedef void (elevator_deactivate_req_fn) (request_queue_t *, struct request *); |
27 | ||
bc1c1169 | 28 | typedef void *(elevator_init_fn) (request_queue_t *, elevator_t *); |
1da177e4 LT |
29 | typedef void (elevator_exit_fn) (elevator_t *); |
30 | ||
31 | struct elevator_ops | |
32 | { | |
33 | elevator_merge_fn *elevator_merge_fn; | |
34 | elevator_merged_fn *elevator_merged_fn; | |
35 | elevator_merge_req_fn *elevator_merge_req_fn; | |
36 | ||
8922e16c | 37 | elevator_dispatch_fn *elevator_dispatch_fn; |
1da177e4 | 38 | elevator_add_req_fn *elevator_add_req_fn; |
8922e16c | 39 | elevator_activate_req_fn *elevator_activate_req_fn; |
1da177e4 LT |
40 | elevator_deactivate_req_fn *elevator_deactivate_req_fn; |
41 | ||
42 | elevator_queue_empty_fn *elevator_queue_empty_fn; | |
43 | elevator_completed_req_fn *elevator_completed_req_fn; | |
44 | ||
45 | elevator_request_list_fn *elevator_former_req_fn; | |
46 | elevator_request_list_fn *elevator_latter_req_fn; | |
47 | ||
48 | elevator_set_req_fn *elevator_set_req_fn; | |
49 | elevator_put_req_fn *elevator_put_req_fn; | |
50 | ||
51 | elevator_may_queue_fn *elevator_may_queue_fn; | |
52 | ||
53 | elevator_init_fn *elevator_init_fn; | |
54 | elevator_exit_fn *elevator_exit_fn; | |
e17a9489 | 55 | void (*trim)(struct io_context *); |
1da177e4 LT |
56 | }; |
57 | ||
58 | #define ELV_NAME_MAX (16) | |
59 | ||
e572ec7e AV |
60 | struct elv_fs_entry { |
61 | struct attribute attr; | |
62 | ssize_t (*show)(elevator_t *, char *); | |
63 | ssize_t (*store)(elevator_t *, const char *, size_t); | |
64 | }; | |
65 | ||
1da177e4 LT |
66 | /* |
67 | * identifies an elevator type, such as AS or deadline | |
68 | */ | |
69 | struct elevator_type | |
70 | { | |
71 | struct list_head list; | |
72 | struct elevator_ops ops; | |
e572ec7e | 73 | struct elv_fs_entry *elevator_attrs; |
1da177e4 LT |
74 | char elevator_name[ELV_NAME_MAX]; |
75 | struct module *elevator_owner; | |
76 | }; | |
77 | ||
78 | /* | |
54069588 | 79 | * each queue has an elevator_queue associated with it |
1da177e4 LT |
80 | */ |
81 | struct elevator_queue | |
82 | { | |
83 | struct elevator_ops *ops; | |
84 | void *elevator_data; | |
85 | struct kobject kobj; | |
86 | struct elevator_type *elevator_type; | |
3d1ab40f | 87 | struct mutex sysfs_lock; |
9817064b | 88 | struct hlist_head *hash; |
1da177e4 LT |
89 | }; |
90 | ||
91 | /* | |
92 | * block elevator interface | |
93 | */ | |
1b47f531 | 94 | extern void elv_dispatch_sort(request_queue_t *, struct request *); |
9817064b | 95 | extern void elv_dispatch_add_tail(request_queue_t *, struct request *); |
1da177e4 LT |
96 | extern void elv_add_request(request_queue_t *, struct request *, int, int); |
97 | extern void __elv_add_request(request_queue_t *, struct request *, int, int); | |
30e9656c | 98 | extern void elv_insert(request_queue_t *, struct request *, int); |
1da177e4 LT |
99 | extern int elv_merge(request_queue_t *, struct request **, struct bio *); |
100 | extern void elv_merge_requests(request_queue_t *, struct request *, | |
101 | struct request *); | |
2e662b65 | 102 | extern void elv_merged_request(request_queue_t *, struct request *, int); |
8922e16c | 103 | extern void elv_dequeue_request(request_queue_t *, struct request *); |
1da177e4 | 104 | extern void elv_requeue_request(request_queue_t *, struct request *); |
1da177e4 LT |
105 | extern int elv_queue_empty(request_queue_t *); |
106 | extern struct request *elv_next_request(struct request_queue *q); | |
107 | extern struct request *elv_former_request(request_queue_t *, struct request *); | |
108 | extern struct request *elv_latter_request(request_queue_t *, struct request *); | |
109 | extern int elv_register_queue(request_queue_t *q); | |
110 | extern void elv_unregister_queue(request_queue_t *q); | |
cb78b285 | 111 | extern int elv_may_queue(request_queue_t *, int); |
1da177e4 | 112 | extern void elv_completed_request(request_queue_t *, struct request *); |
cb78b285 | 113 | extern int elv_set_request(request_queue_t *, struct request *, gfp_t); |
1da177e4 LT |
114 | extern void elv_put_request(request_queue_t *, struct request *); |
115 | ||
116 | /* | |
117 | * io scheduler registration | |
118 | */ | |
119 | extern int elv_register(struct elevator_type *); | |
120 | extern void elv_unregister(struct elevator_type *); | |
121 | ||
122 | /* | |
123 | * io scheduler sysfs switching | |
124 | */ | |
125 | extern ssize_t elv_iosched_show(request_queue_t *, char *); | |
126 | extern ssize_t elv_iosched_store(request_queue_t *, const char *, size_t); | |
127 | ||
128 | extern int elevator_init(request_queue_t *, char *); | |
129 | extern void elevator_exit(elevator_t *); | |
130 | extern int elv_rq_merge_ok(struct request *, struct bio *); | |
1da177e4 | 131 | |
2e662b65 JA |
132 | /* |
133 | * Helper functions. | |
134 | */ | |
135 | extern struct request *elv_rb_former_request(request_queue_t *, struct request *); | |
136 | extern struct request *elv_rb_latter_request(request_queue_t *, struct request *); | |
137 | ||
138 | /* | |
139 | * rb support functions. | |
140 | */ | |
141 | extern struct request *elv_rb_add(struct rb_root *, struct request *); | |
142 | extern void elv_rb_del(struct rb_root *, struct request *); | |
143 | extern struct request *elv_rb_find(struct rb_root *, sector_t); | |
144 | ||
1da177e4 LT |
145 | /* |
146 | * Return values from elevator merger | |
147 | */ | |
148 | #define ELEVATOR_NO_MERGE 0 | |
149 | #define ELEVATOR_FRONT_MERGE 1 | |
150 | #define ELEVATOR_BACK_MERGE 2 | |
151 | ||
152 | /* | |
153 | * Insertion selection | |
154 | */ | |
155 | #define ELEVATOR_INSERT_FRONT 1 | |
156 | #define ELEVATOR_INSERT_BACK 2 | |
157 | #define ELEVATOR_INSERT_SORT 3 | |
797e7dbb | 158 | #define ELEVATOR_INSERT_REQUEUE 4 |
1da177e4 LT |
159 | |
160 | /* | |
161 | * return values from elevator_may_queue_fn | |
162 | */ | |
163 | enum { | |
164 | ELV_MQUEUE_MAY, | |
165 | ELV_MQUEUE_NO, | |
166 | ELV_MQUEUE_MUST, | |
167 | }; | |
168 | ||
1b47f531 | 169 | #define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors) |
2e662b65 | 170 | #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) |
1b47f531 | 171 | |
1fbfdfcd JA |
172 | /* |
173 | * Hack to reuse the donelist list_head as the fifo time holder while | |
174 | * the request is in the io scheduler. Saves an unsigned long in rq. | |
175 | */ | |
176 | #define rq_fifo_time(rq) ((unsigned long) (rq)->donelist.next) | |
177 | #define rq_set_fifo_time(rq,exp) ((rq)->donelist.next = (void *) (exp)) | |
178 | #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) | |
179 | #define rq_fifo_clear(rq) do { \ | |
180 | list_del_init(&(rq)->queuelist); \ | |
181 | INIT_LIST_HEAD(&(rq)->donelist); \ | |
182 | } while (0) | |
183 | ||
4a893e83 JA |
184 | /* |
185 | * io context count accounting | |
186 | */ | |
187 | #define elv_ioc_count_mod(name, __val) \ | |
188 | do { \ | |
189 | preempt_disable(); \ | |
190 | __get_cpu_var(name) += (__val); \ | |
191 | preempt_enable(); \ | |
192 | } while (0) | |
193 | ||
194 | #define elv_ioc_count_inc(name) elv_ioc_count_mod(name, 1) | |
195 | #define elv_ioc_count_dec(name) elv_ioc_count_mod(name, -1) | |
196 | ||
197 | #define elv_ioc_count_read(name) \ | |
198 | ({ \ | |
199 | unsigned long __val = 0; \ | |
200 | int __cpu; \ | |
201 | smp_wmb(); \ | |
202 | for_each_possible_cpu(__cpu) \ | |
203 | __val += per_cpu(name, __cpu); \ | |
204 | __val; \ | |
205 | }) | |
206 | ||
9361401e | 207 | #endif /* CONFIG_BLOCK */ |
1da177e4 | 208 | #endif |