Re: [PATCH Linux 2.6.12-rc6-mm1 06/06] blk: remove last_merge handling from cfq iosched

[Tejun Heo <htejun@gmail.com>]

06_blk_last_merge_consolidation_cfq.patch

	Remove last_merge handling from cfq iosched

Signed-off-by: Tejun Heo <htejun@gmail.com>

 cfq-iosched.c |   22 ++++------------------
 1 files changed, 4 insertions(+), 18 deletions(-)

Index: blk-fixes/drivers/block/cfq-iosched.c
===================================================================
--- blk-fixes.orig/drivers/block/cfq-iosched.c	2005-06-16 13:55:38.000000000 +0900
+++ blk-fixes/drivers/block/cfq-iosched.c	2005-06-16 13:55:39.000000000 +0900
@@ -598,28 +598,20 @@ cfq_merge(request_queue_t *q, struct req
 	struct request *__rq;
 	int ret;
 
-	ret = elv_try_last_merge(q, bio);
-	if (ret != ELEVATOR_NO_MERGE) {
-		__rq = q->last_merge;
-		goto out_insert;
-	}
-
 	__rq = cfq_find_rq_hash(cfqd, bio->bi_sector);
 	if (__rq && elv_rq_merge_ok(__rq, bio)) {
 		ret = ELEVATOR_BACK_MERGE;
-		goto out;
+		goto found;
 	}
 
 	__rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio));
 	if (__rq && elv_rq_merge_ok(__rq, bio)) {
 		ret = ELEVATOR_FRONT_MERGE;
-		goto out;
+		goto found;
 	}
 
 	return ELEVATOR_NO_MERGE;
-out:
-	q->last_merge = __rq;
-out_insert:
+ found:
 	*req = __rq;
 	return ret;
 }
@@ -638,8 +630,6 @@ static void cfq_merged_request(request_q
 		cfq_update_next_crq(crq);
 		cfq_reposition_crq_rb(cfqq, crq);
 	}
-
-	q->last_merge = req;
 }
 
 static void
@@ -1544,13 +1534,9 @@ static void cfq_insert_request(request_q
 
 	list_add_tail(&rq->queuelist, &cfqq->fifo);
 
-	if (rq_mergeable(rq)) {
+	if (rq_mergeable(rq))
 		cfq_add_crq_hash(cfqd, crq);
 
-		if (!cfqd->queue->last_merge)
-			cfqd->queue->last_merge = rq;
-	}
-
 	cfq_crq_enqueued(cfqd, cfqq, crq);
 }