1 files changed, 37 insertions, 0 deletions

diff --git a/block/blk-merge.c b/block/blk-merge.c
index cfcc37cb222b..160035f54882 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;
+}