#ifndef _LINUX_ELEVATOR_H #define _LINUX_ELEVATOR_H #include <linux/percpu.h> #ifdef CONFIG_BLOCK struct io_cq; typedef int (elevator_merge_fn) (struct request_queue *, struct request **, struct bio *); typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *); typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int); typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *); typedef void (elevator_bio_merged_fn) (struct request_queue *, struct request *, struct bio *); typedef int (elevator_dispatch_fn) (struct request_queue *, int); typedef void (elevator_add_req_fn) (struct request_queue *, struct request *); typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *); typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *); typedef int (elevator_may_queue_fn) (struct request_queue *, int); typedef void (elevator_init_icq_fn) (struct io_cq *); typedef void (elevator_exit_icq_fn) (struct io_cq *); typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, gfp_t); typedef void (elevator_put_req_fn) (struct request *); typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *); typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *); typedef void *(elevator_init_fn) (struct request_queue *); typedef void (elevator_exit_fn) (struct elevator_queue *); struct elevator_ops { elevator_merge_fn *elevator_merge_fn; elevator_merged_fn *elevator_merged_fn; elevator_merge_req_fn *elevator_merge_req_fn; elevator_allow_merge_fn *elevator_allow_merge_fn; elevator_bio_merged_fn *elevator_bio_merged_fn; elevator_dispatch_fn *elevator_dispatch_fn; elevator_add_req_fn *elevator_add_req_fn; elevator_activate_req_fn *elevator_activate_req_fn; elevator_deactivate_req_fn *elevator_deactivate_req_fn; elevator_completed_req_fn *elevator_completed_req_fn; elevator_request_list_fn *elevator_former_req_fn; elevator_request_list_fn *elevator_latter_req_fn; elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */ elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */ elevator_set_req_fn *elevator_set_req_fn; elevator_put_req_fn *elevator_put_req_fn; elevator_may_queue_fn *elevator_may_queue_fn; elevator_init_fn *elevator_init_fn; elevator_exit_fn *elevator_exit_fn; }; #define ELV_NAME_MAX (16) struct elv_fs_entry { struct attribute attr; ssize_t (*show)(struct elevator_queue *, char *); ssize_t (*store)(struct elevator_queue *, const char *, size_t); }; /* * identifies an elevator type, such as AS or deadline */ struct elevator_type { /* managed by elevator core */ struct kmem_cache *icq_cache; /* fields provided by elevator implementation */ struct elevator_ops ops; size_t icq_size; /* see iocontext.h */ size_t icq_align; /* ditto */ struct elv_fs_entry *elevator_attrs; char elevator_name[ELV_NAME_MAX]; struct module *elevator_owner; /* managed by elevator core */ char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */ struct list_head list; }; /* * each queue has an elevator_queue associated with it */ struct elevator_queue { struct elevator_type *type; void *elevator_data; struct kobject kobj; struct mutex sysfs_lock; struct hlist_head *hash; unsigned int registered:1; }; /* * block elevator interface */ extern void elv_dispatch_sort(struct request_queue *, struct request *); extern void elv_dispatch_add_tail(struct request_queue *, struct request *); extern void elv_add_request(struct request_queue *, struct request *, int); extern void __elv_add_request(struct request_queue *, struct request *, int); extern int elv_merge(struct request_queue *, struct request **, struct bio *); extern void elv_merge_requests(struct request_queue *, struct request *, struct request *); extern void elv_merged_request(struct request_queue *, struct request *, int); extern void elv_bio_merged(struct request_queue *q, struct request *, struct bio *); extern void elv_requeue_request(struct request_queue *, struct request *); extern struct request *elv_former_request(struct request_queue *, struct request *); extern struct request *elv_latter_request(struct request_queue *, struct request *); extern int elv_register_queue(struct request_queue *q); extern void elv_unregister_queue(struct request_queue *q); extern int elv_may_queue(struct request_queue *, int); extern void elv_abort_queue(struct request_queue *); extern void elv_completed_request(struct request_queue *, struct request *); extern int elv_set_request(struct request_queue *, struct request *, gfp_t); extern void elv_put_request(struct request_queue *, struct request *); extern void elv_drain_elevator(struct request_queue *); /* * io scheduler registration */ extern int elv_register(struct elevator_type *); extern void elv_unregister(struct elevator_type *); /* * io scheduler sysfs switching */ extern ssize_t elv_iosched_show(struct request_queue *, char *); extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); extern int elevator_init(struct request_queue *, char *); extern void elevator_exit(struct elevator_queue *); extern int elevator_change(struct request_queue *, const char *); extern bool elv_rq_merge_ok(struct request *, struct bio *); /* * Helper functions. */ extern struct request *elv_rb_former_request(struct request_queue *, struct request *); extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); /* * rb support functions. */ extern void elv_rb_add(struct rb_root *, struct request *); extern void elv_rb_del(struct rb_root *, struct request *); extern struct request *elv_rb_find(struct rb_root *, sector_t); /* * Return values from elevator merger */ #define ELEVATOR_NO_MERGE 0 #define ELEVATOR_FRONT_MERGE 1 #define ELEVATOR_BACK_MERGE 2 /* * Insertion selection */ #define ELEVATOR_INSERT_FRONT 1 #define ELEVATOR_INSERT_BACK 2 #define ELEVATOR_INSERT_SORT 3 #define ELEVATOR_INSERT_REQUEUE 4 #define ELEVATOR_INSERT_FLUSH 5 #define ELEVATOR_INSERT_SORT_MERGE 6 /* * return values from elevator_may_queue_fn */ enum { ELV_MQUEUE_MAY, ELV_MQUEUE_NO, ELV_MQUEUE_MUST, }; #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq)) #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) /* * Hack to reuse the csd.list list_head as the fifo time holder while * the request is in the io scheduler. Saves an unsigned long in rq. */ #define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next) #define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp)) #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) #define rq_fifo_clear(rq) do { \ list_del_init(&(rq)->queuelist); \ INIT_LIST_HEAD(&(rq)->csd.list); \ } while (0) #endif /* CONFIG_BLOCK */ #endif