typedef void (elevator_put_req_fn) (request_queue_t *, struct request *);
typedef int (elevator_init_fn) (request_queue_t *, elevator_t *);
-typedef void (elevator_exit_fn) (request_queue_t *, elevator_t *);
+typedef void (elevator_exit_fn) (elevator_t *);
-struct elevator_s
+struct elevator_ops
{
elevator_merge_fn *elevator_merge_fn;
elevator_merged_fn *elevator_merged_fn;
elevator_init_fn *elevator_init_fn;
elevator_exit_fn *elevator_exit_fn;
+};
- void *elevator_data;
+#define ELV_NAME_MAX (16)
- struct kobject kobj;
+/*
+ * 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;
- const char *elevator_name;
+ 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;
};
/*
extern void elv_put_request(request_queue_t *, struct request *);
/*
- * noop I/O scheduler. always merges, always inserts new request at tail
- */
-extern elevator_t elevator_noop;
-
-/*
- * deadline i/o scheduler. uses request time outs to prevent indefinite
- * starvation
+ * io scheduler registration
*/
-extern elevator_t iosched_deadline;
+extern int elv_register(struct elevator_type *);
+extern void elv_unregister(struct elevator_type *);
/*
- * anticipatory I/O scheduler
+ * io scheduler sysfs switching
*/
-extern elevator_t iosched_as;
+extern ssize_t elv_iosched_show(request_queue_t *, char *);
+extern ssize_t elv_iosched_store(request_queue_t *, const char *, size_t);
-/*
- * completely fair queueing I/O scheduler
- */
-extern elevator_t iosched_cfq;
-
-extern int elevator_init(request_queue_t *, elevator_t *);
-extern void elevator_exit(request_queue_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 *);
#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