1 #ifndef _LINUX_ELEVATOR_H 2 #define _LINUX_ELEVATOR_H 3 4 #include <linux/percpu.h> 5 6 #ifdef CONFIG_BLOCK 7 8 struct io_cq; 9 10 typedef int (elevator_merge_fn) (struct request_queue *, struct request **, 11 struct bio *); 12 13 typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *); 14 15 typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int); 16 17 typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *); 18 19 typedef void (elevator_bio_merged_fn) (struct request_queue *, 20 struct request *, struct bio *); 21 22 typedef int (elevator_dispatch_fn) (struct request_queue *, int); 23 24 typedef void (elevator_add_req_fn) (struct request_queue *, struct request *); 25 typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *); 26 typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *); 27 typedef int (elevator_may_queue_fn) (struct request_queue *, int); 28 29 typedef void (elevator_init_icq_fn) (struct io_cq *); 30 typedef void (elevator_exit_icq_fn) (struct io_cq *); 31 typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, gfp_t); 32 typedef void (elevator_put_req_fn) (struct request *); 33 typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *); 34 typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *); 35 36 typedef void *(elevator_init_fn) (struct request_queue *); 37 typedef void (elevator_exit_fn) (struct elevator_queue *); 38 39 struct elevator_ops 40 { 41 elevator_merge_fn *elevator_merge_fn; 42 elevator_merged_fn *elevator_merged_fn; 43 elevator_merge_req_fn *elevator_merge_req_fn; 44 elevator_allow_merge_fn *elevator_allow_merge_fn; 45 elevator_bio_merged_fn *elevator_bio_merged_fn; 46 47 elevator_dispatch_fn *elevator_dispatch_fn; 48 elevator_add_req_fn *elevator_add_req_fn; 49 elevator_activate_req_fn *elevator_activate_req_fn; 50 elevator_deactivate_req_fn *elevator_deactivate_req_fn; 51 52 elevator_completed_req_fn *elevator_completed_req_fn; 53 54 elevator_request_list_fn *elevator_former_req_fn; 55 elevator_request_list_fn *elevator_latter_req_fn; 56 57 elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */ 58 elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */ 59 60 elevator_set_req_fn *elevator_set_req_fn; 61 elevator_put_req_fn *elevator_put_req_fn; 62 63 elevator_may_queue_fn *elevator_may_queue_fn; 64 65 elevator_init_fn *elevator_init_fn; 66 elevator_exit_fn *elevator_exit_fn; 67 }; 68 69 #define ELV_NAME_MAX (16) 70 71 struct elv_fs_entry { 72 struct attribute attr; 73 ssize_t (*show)(struct elevator_queue *, char *); 74 ssize_t (*store)(struct elevator_queue *, const char *, size_t); 75 }; 76 77 /* 78 * identifies an elevator type, such as AS or deadline 79 */ 80 struct elevator_type 81 { 82 /* managed by elevator core */ 83 struct kmem_cache *icq_cache; 84 85 /* fields provided by elevator implementation */ 86 struct elevator_ops ops; 87 size_t icq_size; /* see iocontext.h */ 88 size_t icq_align; /* ditto */ 89 struct elv_fs_entry *elevator_attrs; 90 char elevator_name[ELV_NAME_MAX]; 91 struct module *elevator_owner; 92 93 /* managed by elevator core */ 94 char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */ 95 struct list_head list; 96 }; 97 98 /* 99 * each queue has an elevator_queue associated with it 100 */ 101 struct elevator_queue 102 { 103 struct elevator_type *type; 104 void *elevator_data; 105 struct kobject kobj; 106 struct mutex sysfs_lock; 107 struct hlist_head *hash; 108 unsigned int registered:1; 109 }; 110 111 /* 112 * block elevator interface 113 */ 114 extern void elv_dispatch_sort(struct request_queue *, struct request *); 115 extern void elv_dispatch_add_tail(struct request_queue *, struct request *); 116 extern void elv_add_request(struct request_queue *, struct request *, int); 117 extern void __elv_add_request(struct request_queue *, struct request *, int); 118 extern int elv_merge(struct request_queue *, struct request **, struct bio *); 119 extern void elv_merge_requests(struct request_queue *, struct request *, 120 struct request *); 121 extern void elv_merged_request(struct request_queue *, struct request *, int); 122 extern void elv_bio_merged(struct request_queue *q, struct request *, 123 struct bio *); 124 extern void elv_requeue_request(struct request_queue *, struct request *); 125 extern struct request *elv_former_request(struct request_queue *, struct request *); 126 extern struct request *elv_latter_request(struct request_queue *, struct request *); 127 extern int elv_register_queue(struct request_queue *q); 128 extern void elv_unregister_queue(struct request_queue *q); 129 extern int elv_may_queue(struct request_queue *, int); 130 extern void elv_abort_queue(struct request_queue *); 131 extern void elv_completed_request(struct request_queue *, struct request *); 132 extern int elv_set_request(struct request_queue *, struct request *, gfp_t); 133 extern void elv_put_request(struct request_queue *, struct request *); 134 extern void elv_drain_elevator(struct request_queue *); 135 136 /* 137 * io scheduler registration 138 */ 139 extern int elv_register(struct elevator_type *); 140 extern void elv_unregister(struct elevator_type *); 141 142 /* 143 * io scheduler sysfs switching 144 */ 145 extern ssize_t elv_iosched_show(struct request_queue *, char *); 146 extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); 147 148 extern int elevator_init(struct request_queue *, char *); 149 extern void elevator_exit(struct elevator_queue *); 150 extern int elevator_change(struct request_queue *, const char *); 151 extern bool elv_rq_merge_ok(struct request *, struct bio *); 152 153 /* 154 * Helper functions. 155 */ 156 extern struct request *elv_rb_former_request(struct request_queue *, struct request *); 157 extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); 158 159 /* 160 * rb support functions. 161 */ 162 extern void elv_rb_add(struct rb_root *, struct request *); 163 extern void elv_rb_del(struct rb_root *, struct request *); 164 extern struct request *elv_rb_find(struct rb_root *, sector_t); 165 166 /* 167 * Return values from elevator merger 168 */ 169 #define ELEVATOR_NO_MERGE 0 170 #define ELEVATOR_FRONT_MERGE 1 171 #define ELEVATOR_BACK_MERGE 2 172 173 /* 174 * Insertion selection 175 */ 176 #define ELEVATOR_INSERT_FRONT 1 177 #define ELEVATOR_INSERT_BACK 2 178 #define ELEVATOR_INSERT_SORT 3 179 #define ELEVATOR_INSERT_REQUEUE 4 180 #define ELEVATOR_INSERT_FLUSH 5 181 #define ELEVATOR_INSERT_SORT_MERGE 6 182 183 /* 184 * return values from elevator_may_queue_fn 185 */ 186 enum { 187 ELV_MQUEUE_MAY, 188 ELV_MQUEUE_NO, 189 ELV_MQUEUE_MUST, 190 }; 191 192 #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq)) 193 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) 194 195 /* 196 * Hack to reuse the csd.list list_head as the fifo time holder while 197 * the request is in the io scheduler. Saves an unsigned long in rq. 198 */ 199 #define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next) 200 #define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp)) 201 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) 202 #define rq_fifo_clear(rq) do { \ 203 list_del_init(&(rq)->queuelist); \ 204 INIT_LIST_HEAD(&(rq)->csd.list); \ 205 } while (0) 206 207 #endif /* CONFIG_BLOCK */ 208 #endif 209