| 1 | #ifndef _LINUX_ELEVATOR_H |
| 2 | #define _LINUX_ELEVATOR_H |
| 3 | |
| 4 | #include <linux/percpu.h> |
| 5 | |
| 6 | #ifdef CONFIG_BLOCK |
| 7 | |
| 8 | typedef int (elevator_merge_fn) (struct request_queue *, struct request **, |
| 9 | struct bio *); |
| 10 | |
| 11 | typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *); |
| 12 | |
| 13 | typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int); |
| 14 | |
| 15 | typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *); |
| 16 | |
| 17 | typedef void (elevator_bio_merged_fn) (struct request_queue *, |
| 18 | struct request *, struct bio *); |
| 19 | |
| 20 | typedef int (elevator_dispatch_fn) (struct request_queue *, int); |
| 21 | |
| 22 | typedef void (elevator_add_req_fn) (struct request_queue *, struct request *); |
| 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); |
| 26 | |
| 27 | typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, gfp_t); |
| 28 | typedef void (elevator_put_req_fn) (struct request *); |
| 29 | typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *); |
| 30 | typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *); |
| 31 | |
| 32 | typedef void *(elevator_init_fn) (struct request_queue *); |
| 33 | typedef void (elevator_exit_fn) (struct elevator_queue *); |
| 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; |
| 40 | elevator_allow_merge_fn *elevator_allow_merge_fn; |
| 41 | elevator_bio_merged_fn *elevator_bio_merged_fn; |
| 42 | |
| 43 | elevator_dispatch_fn *elevator_dispatch_fn; |
| 44 | elevator_add_req_fn *elevator_add_req_fn; |
| 45 | elevator_activate_req_fn *elevator_activate_req_fn; |
| 46 | elevator_deactivate_req_fn *elevator_deactivate_req_fn; |
| 47 | |
| 48 | elevator_completed_req_fn *elevator_completed_req_fn; |
| 49 | |
| 50 | elevator_request_list_fn *elevator_former_req_fn; |
| 51 | elevator_request_list_fn *elevator_latter_req_fn; |
| 52 | |
| 53 | elevator_set_req_fn *elevator_set_req_fn; |
| 54 | elevator_put_req_fn *elevator_put_req_fn; |
| 55 | |
| 56 | elevator_may_queue_fn *elevator_may_queue_fn; |
| 57 | |
| 58 | elevator_init_fn *elevator_init_fn; |
| 59 | elevator_exit_fn *elevator_exit_fn; |
| 60 | void (*trim)(struct io_context *); |
| 61 | }; |
| 62 | |
| 63 | #define ELV_NAME_MAX (16) |
| 64 | |
| 65 | struct elv_fs_entry { |
| 66 | struct attribute attr; |
| 67 | ssize_t (*show)(struct elevator_queue *, char *); |
| 68 | ssize_t (*store)(struct elevator_queue *, const char *, size_t); |
| 69 | }; |
| 70 | |
| 71 | /* |
| 72 | * identifies an elevator type, such as AS or deadline |
| 73 | */ |
| 74 | struct elevator_type |
| 75 | { |
| 76 | struct list_head list; |
| 77 | struct elevator_ops ops; |
| 78 | struct elv_fs_entry *elevator_attrs; |
| 79 | char elevator_name[ELV_NAME_MAX]; |
| 80 | struct module *elevator_owner; |
| 81 | }; |
| 82 | |
| 83 | /* |
| 84 | * each queue has an elevator_queue associated with it |
| 85 | */ |
| 86 | struct elevator_queue |
| 87 | { |
| 88 | struct elevator_ops *ops; |
| 89 | void *elevator_data; |
| 90 | struct kobject kobj; |
| 91 | struct elevator_type *elevator_type; |
| 92 | struct mutex sysfs_lock; |
| 93 | struct hlist_head *hash; |
| 94 | unsigned int registered:1; |
| 95 | }; |
| 96 | |
| 97 | /* |
| 98 | * block elevator interface |
| 99 | */ |
| 100 | extern void elv_dispatch_sort(struct request_queue *, struct request *); |
| 101 | extern void elv_dispatch_add_tail(struct request_queue *, struct request *); |
| 102 | extern void elv_add_request(struct request_queue *, struct request *, int); |
| 103 | extern void __elv_add_request(struct request_queue *, struct request *, int); |
| 104 | extern int elv_merge(struct request_queue *, struct request **, struct bio *); |
| 105 | extern int elv_try_merge(struct request *, struct bio *); |
| 106 | extern void elv_merge_requests(struct request_queue *, struct request *, |
| 107 | struct request *); |
| 108 | extern void elv_merged_request(struct request_queue *, struct request *, int); |
| 109 | extern void elv_bio_merged(struct request_queue *q, struct request *, |
| 110 | struct bio *); |
| 111 | extern void elv_requeue_request(struct request_queue *, struct request *); |
| 112 | extern struct request *elv_former_request(struct request_queue *, struct request *); |
| 113 | extern struct request *elv_latter_request(struct request_queue *, struct request *); |
| 114 | extern int elv_register_queue(struct request_queue *q); |
| 115 | extern void elv_unregister_queue(struct request_queue *q); |
| 116 | extern int elv_may_queue(struct request_queue *, int); |
| 117 | extern void elv_abort_queue(struct request_queue *); |
| 118 | extern void elv_completed_request(struct request_queue *, struct request *); |
| 119 | extern int elv_set_request(struct request_queue *, struct request *, gfp_t); |
| 120 | extern void elv_put_request(struct request_queue *, struct request *); |
| 121 | extern void elv_drain_elevator(struct request_queue *); |
| 122 | |
| 123 | /* |
| 124 | * io scheduler registration |
| 125 | */ |
| 126 | extern void elv_register(struct elevator_type *); |
| 127 | extern void elv_unregister(struct elevator_type *); |
| 128 | |
| 129 | /* |
| 130 | * io scheduler sysfs switching |
| 131 | */ |
| 132 | extern ssize_t elv_iosched_show(struct request_queue *, char *); |
| 133 | extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); |
| 134 | |
| 135 | extern int elevator_init(struct request_queue *, char *); |
| 136 | extern void elevator_exit(struct elevator_queue *); |
| 137 | extern int elevator_change(struct request_queue *, const char *); |
| 138 | extern int elv_rq_merge_ok(struct request *, struct bio *); |
| 139 | |
| 140 | /* |
| 141 | * Helper functions. |
| 142 | */ |
| 143 | extern struct request *elv_rb_former_request(struct request_queue *, struct request *); |
| 144 | extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); |
| 145 | |
| 146 | /* |
| 147 | * rb support functions. |
| 148 | */ |
| 149 | extern void elv_rb_add(struct rb_root *, struct request *); |
| 150 | extern void elv_rb_del(struct rb_root *, struct request *); |
| 151 | extern struct request *elv_rb_find(struct rb_root *, sector_t); |
| 152 | |
| 153 | /* |
| 154 | * Return values from elevator merger |
| 155 | */ |
| 156 | #define ELEVATOR_NO_MERGE 0 |
| 157 | #define ELEVATOR_FRONT_MERGE 1 |
| 158 | #define ELEVATOR_BACK_MERGE 2 |
| 159 | |
| 160 | /* |
| 161 | * Insertion selection |
| 162 | */ |
| 163 | #define ELEVATOR_INSERT_FRONT 1 |
| 164 | #define ELEVATOR_INSERT_BACK 2 |
| 165 | #define ELEVATOR_INSERT_SORT 3 |
| 166 | #define ELEVATOR_INSERT_REQUEUE 4 |
| 167 | #define ELEVATOR_INSERT_FLUSH 5 |
| 168 | #define ELEVATOR_INSERT_SORT_MERGE 6 |
| 169 | |
| 170 | /* |
| 171 | * return values from elevator_may_queue_fn |
| 172 | */ |
| 173 | enum { |
| 174 | ELV_MQUEUE_MAY, |
| 175 | ELV_MQUEUE_NO, |
| 176 | ELV_MQUEUE_MUST, |
| 177 | }; |
| 178 | |
| 179 | #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq)) |
| 180 | #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) |
| 181 | |
| 182 | /* |
| 183 | * Hack to reuse the csd.list list_head as the fifo time holder while |
| 184 | * the request is in the io scheduler. Saves an unsigned long in rq. |
| 185 | */ |
| 186 | #define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next) |
| 187 | #define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp)) |
| 188 | #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) |
| 189 | #define rq_fifo_clear(rq) do { \ |
| 190 | list_del_init(&(rq)->queuelist); \ |
| 191 | INIT_LIST_HEAD(&(rq)->csd.list); \ |
| 192 | } while (0) |
| 193 | |
| 194 | /* |
| 195 | * io context count accounting |
| 196 | */ |
| 197 | #define elv_ioc_count_mod(name, __val) this_cpu_add(name, __val) |
| 198 | #define elv_ioc_count_inc(name) this_cpu_inc(name) |
| 199 | #define elv_ioc_count_dec(name) this_cpu_dec(name) |
| 200 | |
| 201 | #define elv_ioc_count_read(name) \ |
| 202 | ({ \ |
| 203 | unsigned long __val = 0; \ |
| 204 | int __cpu; \ |
| 205 | smp_wmb(); \ |
| 206 | for_each_possible_cpu(__cpu) \ |
| 207 | __val += per_cpu(name, __cpu); \ |
| 208 | __val; \ |
| 209 | }) |
| 210 | |
| 211 | #endif /* CONFIG_BLOCK */ |
| 212 | #endif |