diff options
Diffstat (limited to 'include/linux/elevator.h')
| -rw-r--r-- | include/linux/elevator.h | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/include/linux/elevator.h b/include/linux/elevator.h new file mode 100644 index 00000000000..ee54f81faad --- /dev/null +++ b/include/linux/elevator.h @@ -0,0 +1,145 @@ +#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); + +typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, 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); +extern void elv_completed_request(request_queue_t *, struct request *); +extern int elv_set_request(request_queue_t *, struct request *, 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 |