block: enumify ELEVATOR_*_MERGE
Switch these constants to an enum, and make let the compiler ensure that
all callers of blk_try_merge and elv_merge handle all potential values.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-mq.c b/block/blk-mq.c
index e9957df..dd9722d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -763,7 +763,7 @@ static bool blk_mq_attempt_merge(struct request_queue *q,
int checked = 8;
list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) {
- int el_ret;
+ bool merged = false;
if (!checked--)
break;
@@ -771,26 +771,22 @@ static bool blk_mq_attempt_merge(struct request_queue *q,
if (!blk_rq_merge_ok(rq, bio))
continue;
- el_ret = blk_try_merge(rq, bio);
- if (el_ret == ELEVATOR_NO_MERGE)
+ switch (blk_try_merge(rq, bio)) {
+ case ELEVATOR_BACK_MERGE:
+ if (blk_mq_sched_allow_merge(q, rq, bio))
+ merged = bio_attempt_back_merge(q, rq, bio);
+ break;
+ case ELEVATOR_FRONT_MERGE:
+ if (blk_mq_sched_allow_merge(q, rq, bio))
+ merged = bio_attempt_front_merge(q, rq, bio);
+ break;
+ default:
continue;
-
- if (!blk_mq_sched_allow_merge(q, rq, bio))
- break;
-
- if (el_ret == ELEVATOR_BACK_MERGE) {
- if (bio_attempt_back_merge(q, rq, bio)) {
- ctx->rq_merged++;
- return true;
- }
- break;
- } else if (el_ret == ELEVATOR_FRONT_MERGE) {
- if (bio_attempt_front_merge(q, rq, bio)) {
- ctx->rq_merged++;
- return true;
- }
- break;
}
+
+ if (merged)
+ ctx->rq_merged++;
+ return merged;
}
return false;
