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 struct request *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 213