1 files changed, 56 insertions, 0 deletions

diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
index f20eba22b14b..e30a3c93b70c 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