From: "Dennis Zhou (Facebook)" <redacted>

This removes the now duplicate association logic in blk-throttle and
blk-iolatency. bio_issue_init is moved into blkcg_bio_issue_check and
into the bio clone variants to allow for the future addition of a
latency moving average for IOs.

Signed-off-by: Dennis Zhou <redacted>
---
 block/bio.c                |  2 ++
 block/blk-iolatency.c      | 24 +-----------------------
 block/blk-throttle.c       | 13 +------------
 block/bounce.c             |  2 ++
 include/linux/blk-cgroup.h |  2 ++
 5 files changed, 8 insertions(+), 35 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index e937f9681188..ab41f5b7eb1f 100644
--- a/block/bio.c
+++ b/block/bio.c

@@ -610,6 +610,8 @@ void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
 	bio->bi_io_vec = bio_src->bi_io_vec;
 
 	bio_clone_blkcg_association(bio, bio_src);
+
+	bio_issue_init(&bio->bi_issue, bio_sectors(bio));
 }
 EXPORT_SYMBOL(__bio_clone_fast);
 

diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 22b2ff0440cc..9d7052bad6f7 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c

@@ -395,34 +395,12 @@ static void blkcg_iolatency_throttle(struct rq_qos *rqos, struct bio *bio,
 				     spinlock_t *lock)
 {
 	struct blk_iolatency *blkiolat = BLKIOLATENCY(rqos);
-	struct blkcg *blkcg;
-	struct blkcg_gq *blkg;
-	struct request_queue *q = rqos->q;
+	struct blkcg_gq *blkg = bio->bi_blkg;
 	bool issue_as_root = bio_issue_as_root_blkg(bio);
 
 	if (!blk_iolatency_enabled(blkiolat))
 		return;
 
-	rcu_read_lock();
-	bio_associate_blkcg(bio, NULL);
-	blkcg = bio_blkcg(bio);
-	blkg = blkg_lookup(blkcg, q);
-	if (unlikely(!blkg)) {
-		if (!lock)
-			spin_lock_irq(q->queue_lock);
-		blkg = __blkg_lookup_create(blkcg, q);
-		if (IS_ERR(blkg))
-			blkg = NULL;
-		if (!lock)
-			spin_unlock_irq(q->queue_lock);
-	}
-	if (!blkg)
-		goto out;
-
-	bio_issue_init(&bio->bi_issue, bio_sectors(bio));
-	bio_associate_blkg(bio, blkg);
-out:
-	rcu_read_unlock();