From: Ashok Vairavan <ashok.vairavan@oracle.com>
Date: Sun, 4 Feb 2018 01:34:38 +0000 (-0800)
Subject: Revert "block: Check for gaps on front and back merges"
X-Git-Tag: v4.1.12-124.31.3~1203
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=0f66af3afeb24a19a90ddbafa6bcf49c2d0df422;p=users%2Fjedix%2Flinux-maple.git

Revert "block: Check for gaps on front and back merges"

This reverts commit 50f113a81b852e45ead0d4b0fd5d79e96530f643.

In UEK4, the decision is made to do complete switch to
queue_virt_boundary discarding the use of SG_GAPS flags. Hence,
this partial porting of new queue limit mask is reverted. Also,
this partial patch is broken for stacked devices.

Orabug: 27484719

Signed-off-by: Ashok Vairavan <ashok.vairavan@oracle.com>
Reviewed-by: Kyle Fortin <kyle.fortin@oracle.com>
---

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 9df4e020fe47..fd3fee81c23c 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -312,8 +312,6 @@ no_merge:
 int ll_back_merge_fn(struct request_queue *q, struct request *req,
 		     struct bio *bio)
 {
-	if (req_gap_back_merge(req, bio))
-		return 0;
 	if (blk_rq_sectors(req) + bio_sectors(bio) >
 	    blk_rq_get_max_sectors(req)) {
 		req->cmd_flags |= REQ_NOMERGE;
@@ -332,9 +330,6 @@ int ll_back_merge_fn(struct request_queue *q, struct request *req,
 int ll_front_merge_fn(struct request_queue *q, struct request *req,
 		      struct bio *bio)
 {
-
-	if (req_gap_front_merge(req, bio))
-		return 0;
 	if (blk_rq_sectors(req) + bio_sectors(bio) >
 	    blk_rq_get_max_sectors(req)) {
 		req->cmd_flags |= REQ_NOMERGE;
@@ -361,6 +356,14 @@ static bool req_no_special_merge(struct request *req)
 	return !q->mq_ops && req->special;
 }
 
+static int req_gap_to_prev(struct request *req, struct request *next)
+{
+	struct bio *prev = req->biotail;
+
+	return bvec_gap_to_prev(&prev->bi_io_vec[prev->bi_vcnt - 1],
+				next->bio->bi_io_vec[0].bv_offset);
+}
+
 static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
 				struct request *next)
 {
@@ -375,7 +378,8 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
 	if (req_no_special_merge(req) || req_no_special_merge(next))
 		return 0;
 
-	if (req_gap_back_merge(req, next->bio))
+	if (test_bit(QUEUE_FLAG_SG_GAPS, &q->queue_flags) &&
+	    req_gap_to_prev(req, next))
 		return 0;
 
 	/*
@@ -585,6 +589,14 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
 	    !blk_write_same_mergeable(rq->bio, bio))
 		return false;
 
+	if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS)) {
+		struct bio_vec *bprev;
+
+		bprev = &rq->biotail->bi_io_vec[rq->biotail->bi_vcnt - 1];
+		if (bvec_gap_to_prev(bprev, bio->bi_io_vec[0].bv_offset))
+			return false;
+	}
+
 	return true;
 }
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 68c78da09c5e..55db2417916a 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1430,29 +1430,6 @@ static inline void put_dev_sector(Sector p)
 	page_cache_release(p.v);
 }
 
-static inline bool bio_will_gap(struct request_queue *q, struct bio *prev,
-			 struct bio *next)
-{
-	if (!bio_has_data(prev))
-		return false;
-
-	if (!test_bit(QUEUE_FLAG_SG_GAPS, &q->queue_flags))
-		return false;
-
-	return bvec_gap_to_prev(&prev->bi_io_vec[prev->bi_vcnt - 1],
-				next->bi_io_vec[0].bv_offset);
-}
-
-static inline bool req_gap_back_merge(struct request *req, struct bio *bio)
-{
-	return bio_will_gap(req->q, req->biotail, bio);
-}
-
-static inline bool req_gap_front_merge(struct request *req, struct bio *bio)
-{
-	return bio_will_gap(req->q, bio, req->bio);
-}
-
 struct work_struct;
 int kblockd_schedule_work(struct work_struct *work);
 int kblockd_schedule_delayed_work(struct delayed_work *dwork, unsigned long delay);