[PATCH] 04/05 remove last_merge handling from ioscheds

Remove last_merge handling from all ioscheds.  This patch
removes merging capability of noop iosched.

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

1 files changed, 4 insertions, 31 deletions

diff --git a/drivers/block/as-iosched.c b/drivers/block/as-iosched.c
index 1775ffe9edc7..5d20e4bcbc78 100644
--- a/drivers/block/as-iosched.c
+++ b/drivers/block/as-iosched.c
@@ -279,14 +279,6 @@ static inline void as_del_arq_hash(struct as_rq *arq)
                 __as_del_arq_hash(arq);
 }
 
-static void as_remove_merge_hints(request_queue_t *q, struct as_rq *arq)
-{
-        as_del_arq_hash(arq);
-
-        if (q->last_merge == arq->request)
-                q->last_merge = NULL;
-}
-
 static void as_add_arq_hash(struct as_data *ad, struct as_rq *arq)
 {
         struct request *rq = arq->request;
@@ -330,7 +322,7 @@ static struct request *as_find_arq_hash(struct as_data *ad, sector_t offset)
                 BUG_ON(!arq->on_hash);
 
                 if (!rq_mergeable(__rq)) {
-                        as_remove_merge_hints(ad->q, arq);
+                        as_del_arq_hash(arq);
                         continue;
                 }
 
@@ -1040,7 +1032,7 @@ static void as_remove_queued_request(request_queue_t *q, struct request *rq)
                 ad->next_arq[data_dir] = as_find_next_arq(ad, arq);
 
         list_del_init(&arq->fifo);
-        as_remove_merge_hints(q, arq);
+        as_del_arq_hash(arq);
         as_del_arq_rb(ad, arq);
 }
 
@@ -1351,7 +1343,7 @@ as_add_aliased_request(struct as_data *ad, struct as_rq *arq, struct as_rq *alia
         /*
          * Don't want to have to handle merges.
          */
-        as_remove_merge_hints(ad->q, arq);
+        as_del_arq_hash(arq);
 }
 
 /*
@@ -1392,12 +1384,8 @@ static void as_add_request(request_queue_t *q, struct request *rq)
                 arq->expires = jiffies + ad->fifo_expire[data_dir];
                 list_add_tail(&arq->fifo, &ad->fifo_list[data_dir]);
 
-                if (rq_mergeable(arq->request)) {
+                if (rq_mergeable(arq->request))
                         as_add_arq_hash(ad, arq);
-
-                        if (!ad->q->last_merge)
-                                ad->q->last_merge = arq->request;
-                }
                 as_update_arq(ad, arq); /* keep state machine up to date */
 
         } else {
@@ -1487,15 +1475,6 @@ as_merge(request_queue_t *q, struct request **req, struct bio *bio)
         int ret;
 
         /*
-         * try last_merge to avoid going to hash
-         */
-        ret = elv_try_last_merge(q, bio);
-        if (ret != ELEVATOR_NO_MERGE) {
-                __rq = q->last_merge;
-                goto out_insert;
-        }
-
-        /*
          * see if the merge hash can satisfy a back merge
          */
         __rq = as_find_arq_hash(ad, bio->bi_sector);
@@ -1523,9 +1502,6 @@ as_merge(request_queue_t *q, struct request **req, struct bio *bio)
 
         return ELEVATOR_NO_MERGE;
 out:
-        if (rq_mergeable(__rq))
-                q->last_merge = __rq;
-out_insert:
         if (ret) {
                 if (rq_mergeable(__rq))
                         as_hot_arq_hash(ad, RQ_DATA(__rq));
@@ -1572,9 +1548,6 @@ static void as_merged_request(request_queue_t *q, struct request *req)
                  * behind the disk head. We currently don't bother adjusting.
                  */
         }
-
-        if (arq->on_hash)
-                q->last_merge = req;
 }
 
 static void