[PATCH] elevator: move the backmerging logic into the elevator core
Right now, every IO scheduler implements its own backmerging (except for
noop, which does no merging). That results in duplicated code for
essentially the same operation, which is never a good thing. This patch
moves the backmerging out of the io schedulers and into the elevator
core. We save 1.6kb of text and as a bonus get backmerging for noop as
well. Win-win!
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 9b91bb7..9cbf7b5 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -281,6 +281,7 @@
{
INIT_LIST_HEAD(&rq->queuelist);
INIT_LIST_HEAD(&rq->donelist);
+ INIT_HLIST_NODE(&rq->hash);
rq->errors = 0;
rq->rq_status = RQ_ACTIVE;
@@ -2700,6 +2701,7 @@
int priv = req->cmd_flags & REQ_ELVPRIV;
BUG_ON(!list_empty(&req->queuelist));
+ BUG_ON(!hlist_unhashed(&req->hash));
blk_free_request(q, req);
freed_request(q, rw, priv);