commit 2e662b65f05d550b6799ed6bfa9963b82279e6b7
author Jens Axboe <axboe@suse.de> Thu Jul 13 11:55:04 2006 +0200
committer Jens Axboe <axboe@nelson.home.kernel.dk> Sat Sep 30 20:26:57 2006 +0200
tree 82911ec73a52d149d74a3d13c3c5eedb269a19cb
parent 10fd48f2376db52f08bf0420d2c4f580e39269e1

[PATCH] elevator: abstract out the rbtree sort handling

The rbtree sort/lookup/reposition logic is mostly duplicated in
cfq/deadline/as, so move it to the elevator core. The io schedulers
still provide the actual rb root, as we don't want to impose any sort
of specific handling on the schedulers.

Introduce the helpers and rb_node in struct request to help migrate the
IO schedulers.

Signed-off-by: Jens Axboe <axboe@suse.de>

include/linux/elevator.h

diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 2c270e9..95b2a04 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -6,7 +6,7 @@
 
 typedef void (elevator_merge_req_fn) (request_queue_t *, struct request *, struct request *);
 
-typedef void (elevator_merged_fn) (request_queue_t *, struct request *);
+typedef void (elevator_merged_fn) (request_queue_t *, struct request *, int);
 
 typedef int (elevator_dispatch_fn) (request_queue_t *, int);
 
@@ -96,7 +96,7 @@
 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_merged_request(request_queue_t *, struct request *, int);
 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 *);
@@ -127,6 +127,19 @@
 extern int elv_rq_merge_ok(struct request *, struct bio *);
 
 /*
+ * Helper functions.
+ */
+extern struct request *elv_rb_former_request(request_queue_t *, struct request *);
+extern struct request *elv_rb_latter_request(request_queue_t *, struct request *);
+
+/*
+ * rb support functions.
+ */
+extern struct request *elv_rb_add(struct rb_root *, struct request *);
+extern void elv_rb_del(struct rb_root *, struct request *);
+extern struct request *elv_rb_find(struct rb_root *, sector_t);
+
+/*
  * Return values from elevator merger
  */
 #define ELEVATOR_NO_MERGE	0
@@ -151,5 +164,6 @@
 };
 
 #define rq_end_sector(rq)	((rq)->sector + (rq)->nr_sectors)
+#define rb_entry_rq(node)	rb_entry((node), struct request, rb_node)
 
 #endif