#ifndef _LINUX_ELEVATOR_H#define _LINUX_ELEVATOR_H typedef int (elevator_merge_fn) (request_queue_t *, struct request **,				 struct bio *); typedef void (elevator_merge_req_fn) (request_queue_t *, struct request *, struct request *); typedef void (elevator_merged_fn) (request_queue_t *, struct request *); typedef struct request *(elevator_next_req_fn) (request_queue_t *); typedef void (elevator_add_req_fn) (request_queue_t *, struct request *, int);typedef int (elevator_queue_empty_fn) (request_queue_t *);typedef void (elevator_remove_req_fn) (request_queue_t *, struct request *);typedef void (elevator_requeue_req_fn) (request_queue_t *, struct request *);typedef struct request *(elevator_request_list_fn) (request_queue_t *, struct request *);typedef void (elevator_completed_req_fn) (request_queue_t *, struct request *);typedef int (elevator_may_queue_fn) (request_queue_t *, int, struct bio *); typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, struct bio *, int);typedef void (elevator_put_req_fn) (request_queue_t *, struct request *);typedef void (elevator_deactivate_req_fn) (request_queue_t *, struct request *); typedef int (elevator_init_fn) (request_queue_t *, elevator_t *);typedef void (elevator_exit_fn) (elevator_t *); struct elevator_ops{	elevator_merge_fn *elevator_merge_fn;	elevator_merged_fn *elevator_merged_fn;	elevator_merge_req_fn *elevator_merge_req_fn; 	elevator_next_req_fn *elevator_next_req_fn;	elevator_add_req_fn *elevator_add_req_fn;	elevator_remove_req_fn *elevator_remove_req_fn;	elevator_requeue_req_fn *elevator_requeue_req_fn;	elevator_deactivate_req_fn *elevator_deactivate_req_fn; 	elevator_queue_empty_fn *elevator_queue_empty_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_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) /* * identifies an elevator type, such as AS or deadline */struct elevator_type{	struct list_head list;	struct elevator_ops ops;	struct elevator_type *elevator_type;	struct kobj_type *elevator_ktype;	char elevator_name[ELV_NAME_MAX];	struct module *elevator_owner;}; /* * each queue has an elevator_queue assoicated with it */struct elevator_queue{	struct elevator_ops *ops;	void *elevator_data;	struct kobject kobj;	struct elevator_type *elevator_type;}; /* * block elevator interface */extern void elv_add_request(request_queue_t *, struct request *, int, int);extern void __elv_add_request(request_queue_t *, struct request *, int, int);extern int elv_merge(request_queue_t *, struct request **, struct bio *);extern void elv_merge_requests(request_queue_t *, struct request *,			       struct request *);extern void elv_merged_request(request_queue_t *, struct request *);extern void elv_remove_request(request_queue_t *, struct request *);extern void elv_requeue_request(request_queue_t *, struct request *);extern void elv_deactivate_request(request_queue_t *, struct request *);extern int elv_queue_empty(request_queue_t *);extern struct request *elv_next_request(struct request_queue *q);extern struct request *elv_former_request(request_queue_t *, struct request *);extern struct request *elv_latter_request(request_queue_t *, struct request *);extern int elv_register_queue(request_queue_t *q);extern void elv_unregister_queue(request_queue_t *q);extern int elv_may_queue(request_queue_t *, int, struct bio *);extern void elv_completed_request(request_queue_t *, struct request *);extern int elv_set_request(request_queue_t *, struct request *, struct bio *, int);extern void elv_put_request(request_queue_t *, struct request *); /* * 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(request_queue_t *, char *);extern ssize_t elv_iosched_store(request_queue_t *, const char *, size_t); extern int elevator_init(request_queue_t *, char *);extern void elevator_exit(elevator_t *);extern int elv_rq_merge_ok(struct request *, struct bio *);extern int elv_try_merge(struct request *, struct bio *);extern int elv_try_last_merge(request_queue_t *, struct bio *); /* * 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 /* * return values from elevator_may_queue_fn */enum {	ELV_MQUEUE_MAY,	ELV_MQUEUE_NO,	ELV_MQUEUE_MUST,}; #endif