linux 2.6.16.38 w/ vs2.0.3-rc1

[linux-2.6.git] / include / linux / elevator.h

diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 27e8183..18cf1f3 100644 (file)
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -8,32 +8,32 @@ typedef void (elevator_merge_req_fn) (request_queue_t *, struct request *, struc
 
 typedef void (elevator_merged_fn) (request_queue_t *, struct request *);
 
-typedef struct request *(elevator_next_req_fn) (request_queue_t *);
+typedef int (elevator_dispatch_fn) (request_queue_t *, int);
 
-typedef void (elevator_add_req_fn) (request_queue_t *, struct request *, int);
+typedef void (elevator_add_req_fn) (request_queue_t *, struct request *);
 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_may_queue_fn) (request_queue_t *, int, struct bio *);
 
-typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, int);
+typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, struct bio *, gfp_t);
 typedef void (elevator_put_req_fn) (request_queue_t *, struct request *);
+typedef void (elevator_activate_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) (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_merge_req_fn *elevator_merge_req_fn;
 
-       elevator_next_req_fn *elevator_next_req_fn;
+       elevator_dispatch_fn *elevator_dispatch_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_activate_req_fn *elevator_activate_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;
@@ -48,24 +48,46 @@ struct elevator_s
 
        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 associated 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_dispatch_sort(request_queue_t *, struct request *);
 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 void elv_insert(request_queue_t *, struct request *, 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_dequeue_request(request_queue_t *, struct request *);
 extern void elv_requeue_request(request_queue_t *, struct request *);
 extern int elv_queue_empty(request_queue_t *);
 extern struct request *elv_next_request(struct request_queue *q);
@@ -73,37 +95,26 @@ 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 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 *, int);
+extern int elv_set_request(request_queue_t *, struct request *, struct bio *, gfp_t);
 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
- */
-extern elevator_t iosched_deadline;
-
-/*
- * anticipatory I/O scheduler
+ * io scheduler registration
  */
-extern elevator_t iosched_as;
+extern int elv_register(struct elevator_type *);
+extern void elv_unregister(struct elevator_type *);
 
 /*
- * completely fair queueing I/O scheduler
+ * io scheduler sysfs switching
  */
-extern elevator_t iosched_cfq;
+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 *, 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 *);
 
 /*
  * Return values from elevator merger
@@ -118,5 +129,17 @@ extern int elv_try_last_merge(request_queue_t *, struct bio *);
 #define ELEVATOR_INSERT_FRONT  1
 #define ELEVATOR_INSERT_BACK   2
 #define ELEVATOR_INSERT_SORT   3
+#define ELEVATOR_INSERT_REQUEUE        4
+
+/*
+ * return values from elevator_may_queue_fn
+ */
+enum {
+       ELV_MQUEUE_MAY,
+       ELV_MQUEUE_NO,
+       ELV_MQUEUE_MUST,
+};
+
+#define rq_end_sector(rq)      ((rq)->sector + (rq)->nr_sectors)
 
 #endif