blk-mq: simplify the plug handling in blk_mq_submit_bio
blk_mq_submit_bio has two different plug cases, one that uses full
plugging and a limited plugging one.
The limited plugging case is only used for a corner case that does
not matter in real life:
- no ->commit_rqs (so not NVMe)
- no shared tags (so not SCSI)
- not rotational (so no old disk or floppy driver)
- must have multiple queues (so no eMMC)
Remove the limited merging case and all the related junk to simplify
blk_mq_submit_bio and the functions called from it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123160443.1315598-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 893c1a6..ba761c3 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -1067,7 +1067,6 @@ static enum bio_merge_status blk_attempt_bio_merge(struct request_queue *q,
* @q: request_queue new bio is being queued at
* @bio: new bio being queued
* @nr_segs: number of segments in @bio
- * @same_queue_rq: output value, will be true if there's an existing request
* from the passed in @q already in the plug list
*
* Determine whether @bio being queued on @q can be merged with the previous
@@ -1084,7 +1083,7 @@ static enum bio_merge_status blk_attempt_bio_merge(struct request_queue *q,
* Caller must ensure !blk_queue_nomerges(q) beforehand.
*/
bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
- unsigned int nr_segs, bool *same_queue_rq)
+ unsigned int nr_segs)
{
struct blk_plug *plug;
struct request *rq;
@@ -1096,12 +1095,6 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
/* check the previously added entry for a quick merge attempt */
rq = rq_list_peek(&plug->mq_list);
if (rq->q == q) {
- /*
- * Only blk-mq multiple hardware queues case checks the rq in
- * the same queue, there should be only one such rq in a queue
- */
- *same_queue_rq = true;
-
if (blk_attempt_bio_merge(q, rq, bio, nr_segs, false) ==
BIO_MERGE_OK)
return true;
