block/blk-core.c          |    2 ++
 block/blk-merge.c         |    9 +++++++++
 include/linux/blk_types.h |    2 +-
 include/linux/blkdev.h    |    1 +
 4 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 4ce953f..a0c13a9 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1323,6 +1323,7 @@ static inline void blk_partition_remap(struct bio *bio)
 {
 	struct block_device *bdev = bio->bi_bdev;
 
+	bio->bi_part = bdev;
 	if (bio_sectors(bio) && bdev != bdev->bd_contains) {
 		struct hd_struct *p = bdev->bd_part;
 
@@ -2437,6 +2438,7 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
 	rq->__data_len = bio->bi_size;
 	rq->bio = rq->biotail = bio;
 
+	rq->rq_part = bio->bi_part;
 	if (bio->bi_bdev)
 		rq->rq_disk = bio->bi_bdev->bd_disk;
 }
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 77b7c26..3913f5f 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -230,6 +230,9 @@ int ll_back_merge_fn(struct request_queue *q, struct request *req,
 {
 	unsigned short max_sectors;
 
+	if (req->rq_part != bio->bi_part)
+		return 0;
+
 	if (unlikely(req->cmd_type == REQ_TYPE_BLOCK_PC))
 		max_sectors = queue_max_hw_sectors(q);
 	else
@@ -254,6 +257,9 @@ int ll_front_merge_fn(struct request_queue *q, struct request *req,
 {
 	unsigned short max_sectors;
 
+	if (bio->bi_part != req->rq_part)
+		return 0;
+
 	if (unlikely(req->cmd_type == REQ_TYPE_BLOCK_PC))
 		max_sectors = queue_max_hw_sectors(q);
 	else
@@ -392,6 +398,9 @@ static int attempt_merge(struct request_queue *q, struct request *req,
 	    || next->special)
 		return 0;
 
+	if (req->rq_part != next->rq_part)
+		return 0;
+
 	/*
 	 * If we are allowed to merge, then append bio list
 	 * from next to rq and release next. merge_requests_fn
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 46ad519..0940480 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -34,7 +34,7 @@ struct bio {
 	sector_t		bi_sector;	/* device address in 512 byte
 						   sectors */
 	struct bio		*bi_next;	/* request queue link */
-	struct block_device	*bi_bdev;
+	struct block_device	*bi_bdev, *bi_part;
 	unsigned long		bi_flags;	/* status, command, etc */
 	unsigned long		bi_rw;		/* bottom bits READ/WRITE,
 						 * top bits priority
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index aae86fd..f31bd4f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -114,6 +114,7 @@ struct request {
 	void *elevator_private2;
 	void *elevator_private3;
 
+	struct block_device *rq_part;
 	struct gendisk *rq_disk;
 	unsigned long start_time;
 #ifdef CONFIG_BLK_CGROUP