[PATCH] 03/05 move last_merge handlin into generic elevator code
Currently, both generic elevator code and specific ioscheds
participate in the management and usage of last_merge. This
and the following patches move last_merge handling into
generic elevator code.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c
index 29d6c82..4151443 100644
--- a/drivers/block/elevator.c
+++ b/drivers/block/elevator.c
@@ -83,15 +83,6 @@
}
EXPORT_SYMBOL(elv_try_merge);
-inline int elv_try_last_merge(request_queue_t *q, struct bio *bio)
-{
- if (q->last_merge)
- return elv_try_merge(q->last_merge, bio);
-
- return ELEVATOR_NO_MERGE;
-}
-EXPORT_SYMBOL(elv_try_last_merge);
-
static struct elevator_type *elevator_find(const char *name)
{
struct elevator_type *e = NULL;
@@ -239,6 +230,9 @@
unsigned max_back;
struct list_head *entry;
+ if (q->last_merge == rq)
+ q->last_merge = NULL;
+
boundary = q->end_sector;
max_back = q->max_back_kb * 2;
boundary = boundary > max_back ? boundary - max_back : 0;
@@ -265,6 +259,15 @@
int elv_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
elevator_t *e = q->elevator;
+ int ret;
+
+ if (q->last_merge) {
+ ret = elv_try_merge(q->last_merge, bio);
+ if (ret != ELEVATOR_NO_MERGE) {
+ *req = q->last_merge;
+ return ret;
+ }
+ }
if (e->ops->elevator_merge_fn)
return e->ops->elevator_merge_fn(q, req, bio);
@@ -278,6 +281,8 @@
if (e->ops->elevator_merged_fn)
e->ops->elevator_merged_fn(q, rq);
+
+ q->last_merge = rq;
}
void elv_merge_requests(request_queue_t *q, struct request *rq,
@@ -285,11 +290,10 @@
{
elevator_t *e = q->elevator;
- if (q->last_merge == next)
- q->last_merge = NULL;
-
if (e->ops->elevator_merge_req_fn)
e->ops->elevator_merge_req_fn(q, rq, next);
+
+ q->last_merge = rq;
}
void elv_requeue_request(request_queue_t *q, struct request *rq)
@@ -384,6 +388,8 @@
BUG_ON(!blk_fs_request(rq));
rq->flags |= REQ_SORTED;
q->elevator->ops->elevator_add_req_fn(q, rq);
+ if (q->last_merge == NULL && rq_mergeable(rq))
+ q->last_merge = rq;
break;
default:
@@ -462,9 +468,6 @@
rq->flags |= REQ_STARTED;
}
- if (rq == q->last_merge)
- q->last_merge = NULL;
-
if (!q->boundary_rq || q->boundary_rq == rq) {
q->end_sector = rq_end_sector(rq);
q->boundary_rq = NULL;
@@ -518,16 +521,6 @@
*/
if (blk_account_rq(rq))
q->in_flight++;
-
- /*
- * the main clearing point for q->last_merge is on retrieval of
- * request by driver (it calls elv_next_request()), but it _can_
- * also happen here if a request is added to the queue but later
- * deleted without ever being given to driver (merged with another
- * request).
- */
- if (rq == q->last_merge)
- q->last_merge = NULL;
}
int elv_queue_empty(request_queue_t *q)