Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #ifndef _LINUX_ELEVATOR_H |
| 2 | #define _LINUX_ELEVATOR_H |
| 3 | |
Jens Axboe | 4a893e8 | 2006-07-22 15:37:43 +0200 | [diff] [blame] | 4 | #include <linux/percpu.h> |
| 5 | |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 6 | #ifdef CONFIG_BLOCK |
| 7 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 13 | typedef void (elevator_merged_fn) (request_queue_t *, struct request *, int); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 15 | typedef int (elevator_dispatch_fn) (request_queue_t *, int); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 17 | typedef void (elevator_add_req_fn) (request_queue_t *, struct request *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 18 | typedef int (elevator_queue_empty_fn) (request_queue_t *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 *); |
Jens Axboe | cb78b28 | 2006-07-28 09:32:57 +0200 | [diff] [blame] | 21 | typedef int (elevator_may_queue_fn) (request_queue_t *, int); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | |
Jens Axboe | cb78b28 | 2006-07-28 09:32:57 +0200 | [diff] [blame] | 23 | typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, gfp_t); |
Jens Axboe | bb37b94 | 2006-12-01 10:42:33 +0100 | [diff] [blame] | 24 | typedef void (elevator_put_req_fn) (struct request *); |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 25 | typedef void (elevator_activate_req_fn) (request_queue_t *, struct request *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | typedef void (elevator_deactivate_req_fn) (request_queue_t *, struct request *); |
| 27 | |
Jens Axboe | bb37b94 | 2006-12-01 10:42:33 +0100 | [diff] [blame] | 28 | typedef void *(elevator_init_fn) (request_queue_t *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 37 | elevator_dispatch_fn *elevator_dispatch_fn; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | elevator_add_req_fn *elevator_add_req_fn; |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 39 | elevator_activate_req_fn *elevator_activate_req_fn; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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; |
Al Viro | e17a948 | 2006-03-18 13:21:20 -0500 | [diff] [blame] | 55 | void (*trim)(struct io_context *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 56 | }; |
| 57 | |
| 58 | #define ELV_NAME_MAX (16) |
| 59 | |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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; |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 73 | struct elv_fs_entry *elevator_attrs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | char elevator_name[ELV_NAME_MAX]; |
| 75 | struct module *elevator_owner; |
| 76 | }; |
| 77 | |
| 78 | /* |
Adrian Bunk | 5406958 | 2006-01-10 00:09:36 +0100 | [diff] [blame] | 79 | * each queue has an elevator_queue associated with it |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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; |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 87 | struct mutex sysfs_lock; |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 88 | struct hlist_head *hash; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | }; |
| 90 | |
| 91 | /* |
| 92 | * block elevator interface |
| 93 | */ |
Jens Axboe | 1b47f53 | 2005-10-20 16:37:00 +0200 | [diff] [blame] | 94 | extern void elv_dispatch_sort(request_queue_t *, struct request *); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 95 | extern void elv_dispatch_add_tail(request_queue_t *, struct request *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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); |
Tejun Heo | 30e9656 | 2006-02-08 01:01:31 -0800 | [diff] [blame] | 98 | extern void elv_insert(request_queue_t *, struct request *, int); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 *); |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 102 | extern void elv_merged_request(request_queue_t *, struct request *, int); |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 103 | extern void elv_dequeue_request(request_queue_t *, struct request *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | extern void elv_requeue_request(request_queue_t *, struct request *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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); |
Jens Axboe | cb78b28 | 2006-07-28 09:32:57 +0200 | [diff] [blame] | 111 | extern int elv_may_queue(request_queue_t *, int); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | extern void elv_completed_request(request_queue_t *, struct request *); |
Jens Axboe | cb78b28 | 2006-07-28 09:32:57 +0200 | [diff] [blame] | 113 | extern int elv_set_request(request_queue_t *, struct request *, gfp_t); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | |
| 132 | /* |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 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 | |
| 145 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 158 | #define ELEVATOR_INSERT_REQUEUE 4 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Jens Axboe | 1b47f53 | 2005-10-20 16:37:00 +0200 | [diff] [blame] | 169 | #define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors) |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 170 | #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) |
Jens Axboe | 1b47f53 | 2005-10-20 16:37:00 +0200 | [diff] [blame] | 171 | |
Jens Axboe | 1fbfdfc | 2006-07-11 21:49:15 +0200 | [diff] [blame] | 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 | |
Jens Axboe | 4a893e8 | 2006-07-22 15:37:43 +0200 | [diff] [blame] | 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 | |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 207 | #endif /* CONFIG_BLOCK */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 208 | #endif |