vserver 1.9.5.x5

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

diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 27e8183..8cf0e3f 100644 (file)
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -22,9 +22,9 @@ typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, int);
 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;
@@ -48,12 +48,32 @@ 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 assoicated with it
+ */
+struct elevator_queue
+{
+       struct elevator_ops *ops;
+       void *elevator_data;
+       struct kobject kobj;
+       struct elevator_type *elevator_type;
 };
 
 /*
@@ -79,28 +99,19 @@ extern int elv_set_request(request_queue_t *, struct request *, int);
 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 *);
@@ -119,4 +130,13 @@ 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