Stop exporting blk_rq_bio_prep

blk_rq_bio_prep is exported for use in exactly
one place.  That place can benefit from using
the new blk_rq_append_bio instead.
So
  - change dm-emc to call blk_rq_append_bio
  - stop exporting blk_rq_bio_prep, and
  - initialise rq_disk in blk_rq_bio_prep,
       as dm-emc needs it.
Signed-off-by: Neil Brown <neilb@suse.de>

diff .prev/block/ll_rw_blk.c ./block/ll_rw_blk.c
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block/ll_rw_blk.c

@@ -43,6 +43,8 @@ static void init_request_from_bio(struct request *req, struct bio *bio);
 static int __make_request(struct request_queue *q, struct bio *bio);
 static struct io_context *current_io_context(gfp_t gfp_flags, int node);
 static void blk_recalc_rq_segments(struct request *rq);
+static void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
+			    struct bio *bio);
 
 /*
  * For the allocated request tables
@@ -3665,8 +3667,8 @@ void end_request(struct request *req, int uptodate)
 
 EXPORT_SYMBOL(end_request);
 
-void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
-		     struct bio *bio)
+static void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
+			    struct bio *bio)
 {
 	/* first two bits are identical in rq->cmd_flags and bio->bi_rw */
 	rq->cmd_flags |= (bio->bi_rw & 3);
@@ -3680,9 +3682,10 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
 	rq->data_len = bio->bi_size;
 
 	rq->bio = rq->biotail = bio;
-}
 
-EXPORT_SYMBOL(blk_rq_bio_prep);
+	if (bio->bi_bdev)
+		rq->rq_disk = bio->bi_bdev->bd_disk;
+}
 
 int kblockd_schedule_work(struct work_struct *work)
 {

drivers/md/dm-emc.c

@@ -109,15 +109,7 @@ static struct request *get_failover_req(struct emc_handler *h,
 		return NULL;
 	}
 
-	rq->bio = rq->biotail = bio;
-	blk_rq_bio_prep(q, rq, bio);
-
-	rq->rq_disk = bdev->bd_contains->bd_disk;
-
-	/* bio backed don't set data */
-	rq->buffer = rq->data = NULL;
-	/* rq data_len used for pc cmd's request_bufflen */
-	rq->data_len = bio->bi_size;
+	blk_rq_append_bio(q, rq, bio);
 
 	rq->sense = h->sense;
 	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);

include/linux/blkdev.h

@@ -823,7 +823,6 @@ static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 	return bqt->tag_index[tag];
 }
 
-extern void blk_rq_bio_prep(struct request_queue *, struct request *, struct bio *);
 extern int blkdev_issue_flush(struct block_device *, sector_t *);
 
 #define MAX_PHYS_SEGMENTS 128