1 files changed, 37 insertions, 0 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c
index cfcc37c..160035f 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -471,3 +471,40 @@ int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 {
 	return attempt_merge(q, rq, next);
 }
+
+bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
+{
+	if (!rq_mergeable(rq))
+		return false;
+
+	/* don't merge file system requests and discard requests */
+	if ((bio->bi_rw & REQ_DISCARD) != (rq->bio->bi_rw & REQ_DISCARD))
+		return false;
+
+	/* don't merge discard requests and secure discard requests */
+	if ((bio->bi_rw & REQ_SECURE) != (rq->bio->bi_rw & REQ_SECURE))
+		return false;
+
+	/* different data direction or already started, don't merge */
+	if (bio_data_dir(bio) != rq_data_dir(rq))
+		return false;
+
+	/* must be same device and not a special request */
+	if (rq->rq_disk != bio->bi_bdev->bd_disk || rq->special)
+		return false;
+
+	/* only merge integrity protected bio into ditto rq */
+	if (bio_integrity(bio) != blk_integrity_rq(rq))
+		return false;
+
+	return true;
+}
+
+int blk_try_merge(struct request *rq, struct bio *bio)
+{
+	if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_sector)
+		return ELEVATOR_BACK_MERGE;
+	else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_sector)
+		return ELEVATOR_FRONT_MERGE;
+	return ELEVATOR_NO_MERGE;
+}