There are lots of duplicated code when trying to merge a bio from
plug list and sw queue, we can introduce a new helper to attempt
to merge a bio, which can simplify the blk_mq_bio_list_merge()
and blk_attempt_plug_merge().
Signed-off-by: Baolin Wang <baolin.w...@linux.alibaba.com>
---
block/blk-merge.c | 47 +++++++++++++++++++++++++++++------------------
block/blk-mq-sched.c | 22 ++++------------------
block/blk.h | 9 +++++++++
3 files changed, 42 insertions(+), 36 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 1993e6a..feaee53 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -975,6 +975,33 @@ bool bio_attempt_discard_merge(struct request_queue *q,
struct request *req,
return false;
}
+enum bio_merge_status blk_attempt_bio_merge(struct request_queue *q,
+ struct request *rq,
+ struct bio *bio,
+ unsigned int nr_segs)
+{
+ bool merged = false;
+
+ if (!blk_rq_merge_ok(rq, bio))
+ return BIO_MERGE_NONE;
+
+ switch (blk_try_merge(rq, bio)) {
+ case ELEVATOR_BACK_MERGE:
+ merged = bio_attempt_back_merge(rq, bio, nr_segs);
+ break;
+ case ELEVATOR_FRONT_MERGE:
+ merged = bio_attempt_front_merge(rq, bio, nr_segs);
+ break;
+ case ELEVATOR_DISCARD_MERGE:
+ merged = bio_attempt_discard_merge(q, rq, bio);
+ break;
+ default:
+ return BIO_MERGE_NONE;
+ }
+
+ return merged ? BIO_MERGE_OK : BIO_MERGE_FAILED;
+}
+
/**
* blk_attempt_plug_merge - try to merge with %current's plugged list
* @q: request_queue new bio is being queued at
@@ -1011,8 +1038,6 @@ bool blk_attempt_plug_merge(struct request_queue *q,
struct bio *bio,
plug_list = &plug->mq_list;
list_for_each_entry_reverse(rq, plug_list, queuelist) {
- bool merged = false;
-
if (rq->q == q && same_queue_rq) {
/*
* Only blk-mq multiple hardware queues case checks the
@@ -1022,24 +1047,10 @@ bool blk_attempt_plug_merge(struct request_queue *q,
struct bio *bio,
*same_queue_rq = rq;
}
- if (rq->q != q || !blk_rq_merge_ok(rq, bio))
+ if (rq->q != q)
continue;
- switch (blk_try_merge(rq, bio)) {
- case ELEVATOR_BACK_MERGE:
- merged = bio_attempt_back_merge(rq, bio, nr_segs);
- break;
- case ELEVATOR_FRONT_MERGE:
- merged = bio_attempt_front_merge(rq, bio, nr_segs);
- break;
- case ELEVATOR_DISCARD_MERGE:
- merged = bio_attempt_discard_merge(q, rq, bio);
- break;
- default:
- break;
- }
-
- if (merged)
+ if (blk_attempt_bio_merge(q, rq, bio, nr_segs) == BIO_MERGE_OK)
return true;
}
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index cc34f69..24d5078 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -391,31 +391,17 @@ bool blk_mq_bio_list_merge(struct request_queue *q,
struct list_head *list,
{
struct request *rq;
int checked = 8;
+ enum bio_merge_status merge;
list_for_each_entry_reverse(rq, list, queuelist) {
- bool merged = false;
-
if (!checked--)
break;
- if (!blk_rq_merge_ok(rq, bio))
+ merge = blk_attempt_bio_merge(q, rq, bio, nr_segs);
+ if (merge == BIO_MERGE_NONE)
continue;
- switch (blk_try_merge(rq, bio)) {
- case ELEVATOR_BACK_MERGE:
- merged = bio_attempt_back_merge(rq, bio, nr_segs);
- break;
- case ELEVATOR_FRONT_MERGE:
- merged = bio_attempt_front_merge(rq, bio, nr_segs);
- break;
- case ELEVATOR_DISCARD_MERGE:
- merged = bio_attempt_discard_merge(q, rq, bio);
- break;
- default:
- continue;
- }
-
- return merged;
+ return merge == BIO_MERGE_OK ? true: false;
}
return false;
diff --git a/block/blk.h b/block/blk.h
index 49e2928..a6c54e1 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -234,6 +234,15 @@ int blk_attempt_req_merge(struct request_queue *q, struct
request *rq,
bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
+enum bio_merge_status {
+ BIO_MERGE_OK,
+ BIO_MERGE_NONE,
+ BIO_MERGE_FAILED,
+};
+
+enum bio_merge_status blk_attempt_bio_merge(struct request_queue *q,
+ struct request *rq, struct bio *bio, unsigned int nr_segs);
+
int blk_dev_init(void);
/*
--
1.8.3.1
