diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
index f20eba22b14..e30a3c93b70 100644
--- a/drivers/block/ll_rw_blk.c
+++ b/drivers/block/ll_rw_blk.c
@@ -281,6 +281,7 @@ static inline void rq_init(request_queue_t *q, struct request *rq)
 	rq->special = NULL;
 	rq->data_len = 0;
 	rq->data = NULL;
+	rq->nr_phys_segments = 0;
 	rq->sense = NULL;
 	rq->end_io = NULL;
 	rq->end_io_data = NULL;
@@ -2176,6 +2177,61 @@ int blk_rq_unmap_user(struct request *rq, struct bio *bio, unsigned int ulen)
 
 EXPORT_SYMBOL(blk_rq_unmap_user);
 
+static int blk_rq_map_kern_endio(struct bio *bio, unsigned int bytes_done,
+				 int error)
+{
+	if (bio->bi_size)
+		return 1;
+
+	bio_put(bio);
+	return 0;
+}
+
+/**
+ * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage
+ * @q:		request queue where request should be inserted
+ * @rw:		READ or WRITE data
+ * @kbuf:	the kernel buffer
+ * @len:	length of user data
+ */
+struct request *blk_rq_map_kern(request_queue_t *q, int rw, void *kbuf,
+				unsigned int len, unsigned int gfp_mask)
+{
+	struct request *rq;
+	struct bio *bio;
+
+	if (len > (q->max_sectors << 9))
+		return ERR_PTR(-EINVAL);
+	if ((!len && kbuf) || (len && !kbuf))
+		return ERR_PTR(-EINVAL);
+
+	rq = blk_get_request(q, rw, gfp_mask);
+	if (!rq)
+		return ERR_PTR(-ENOMEM);
+
+	bio = bio_map_kern(q, kbuf, len, gfp_mask);
+	if (!IS_ERR(bio)) {
+		if (rw)
+			bio->bi_rw |= (1 << BIO_RW);
+		bio->bi_end_io = blk_rq_map_kern_endio;
+
+		rq->bio = rq->biotail = bio;
+		blk_rq_bio_prep(q, rq, bio);
+
+		rq->buffer = rq->data = NULL;
+		rq->data_len = len;
+		return rq;
+	}
+
+	/*
+	 * bio is the err-ptr
+	 */
+	blk_put_request(rq);
+	return (struct request *) bio;
+}
+
+EXPORT_SYMBOL(blk_rq_map_kern);
+
 /**
  * blk_execute_rq - insert a request into queue for execution
  * @q:		queue to insert the request in
diff --git a/fs/bio.c b/fs/bio.c
index 3a1472acc36..707b9af2dd0 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -701,6 +701,71 @@ void bio_unmap_user(struct bio *bio)
 	bio_put(bio);
 }
 
+static struct bio *__bio_map_kern(request_queue_t *q, void *data,
+				  unsigned int len, unsigned int gfp_mask)
+{
+	unsigned long kaddr = (unsigned long)data;
+	unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	unsigned long start = kaddr >> PAGE_SHIFT;
+	const int nr_pages = end - start;
+	int offset, i;
+	struct bio *bio;
+
+	bio = bio_alloc(gfp_mask, nr_pages);
+	if (!bio)
+		return ERR_PTR(-ENOMEM);
+
+	offset = offset_in_page(kaddr);
+	for (i = 0; i < nr_pages; i++) {
+		unsigned int bytes = PAGE_SIZE - offset;
+
+		if (len <= 0)
+			break;
+
+		if (bytes > len)
+			bytes = len;
+
+		if (__bio_add_page(q, bio, virt_to_page(data), bytes,
+				   offset) < bytes)
+			break;
+
+		data += bytes;
+		len -= bytes;
+		offset = 0;
+	}
+
+	return bio;
+}
+
+/**
+ *	bio_map_kern	-	map kernel address into bio
+ *	@q: the request_queue_t for the bio
+ *	@data: pointer to buffer to map
+ *	@len: length in bytes
+ *	@gfp_mask: allocation flags for bio allocation
+ *
+ *	Map the kernel address into a bio suitable for io to a block
+ *	device. Returns an error pointer in case of error.
+ */
+struct bio *bio_map_kern(request_queue_t *q, void *data, unsigned int len,
+			 unsigned int gfp_mask)
+{
+	struct bio *bio;
+
+	bio = __bio_map_kern(q, data, len, gfp_mask);
+	if (IS_ERR(bio))
+		return bio;
+
+	if (bio->bi_size == len)
+		return bio;
+
+	/*
+	 * Don't support partial mappings.
+	 */
+	bio_put(bio);
+	return ERR_PTR(-EINVAL);
+}
+
 /*
  * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
  * for performing direct-IO in BIOs.
@@ -1088,6 +1153,7 @@ EXPORT_SYMBOL(bio_add_page);
 EXPORT_SYMBOL(bio_get_nr_vecs);
 EXPORT_SYMBOL(bio_map_user);
 EXPORT_SYMBOL(bio_unmap_user);
+EXPORT_SYMBOL(bio_map_kern);
 EXPORT_SYMBOL(bio_pair_release);
 EXPORT_SYMBOL(bio_split);
 EXPORT_SYMBOL(bio_split_pool);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 038022763f0..1dd2bc2e84a 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -282,6 +282,8 @@ extern int bio_get_nr_vecs(struct block_device *);
 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
 				unsigned long, unsigned int, int);
 extern void bio_unmap_user(struct bio *);
+extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
+				unsigned int);
 extern void bio_set_pages_dirty(struct bio *bio);
 extern void bio_check_pages_dirty(struct bio *bio);
 extern struct bio *bio_copy_user(struct request_queue *, unsigned long, unsigned int, int);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 4a99b76c5a3..67339bc5f6b 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -560,6 +560,8 @@ extern void blk_run_queue(request_queue_t *);
 extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *);
 extern struct request *blk_rq_map_user(request_queue_t *, int, void __user *, unsigned int);
 extern int blk_rq_unmap_user(struct request *, struct bio *, unsigned int);
+extern struct request *blk_rq_map_kern(request_queue_t *, int, void *,
+					unsigned int, unsigned int);
 extern int blk_execute_rq(request_queue_t *, struct gendisk *, struct request *);
 
 static inline request_queue_t *bdev_get_queue(struct block_device *bdev)