scsi: set sc_data_direction in common code

The data direction fiel in the SCSI command is derived only from the block
request structure.  Move setting it up into common code instead of
duplicating it in the ULDs.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>

drivers/scsi/scsi_lib.c

@@ -1068,13 +1068,6 @@ int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
 	}
 
 	cmd->cmd_len = req->cmd_len;
-	if (!blk_rq_bytes(req))
-		cmd->sc_data_direction = DMA_NONE;
-	else if (rq_data_dir(req) == WRITE)
-		cmd->sc_data_direction = DMA_TO_DEVICE;
-	else
-		cmd->sc_data_direction = DMA_FROM_DEVICE;
-	
 	cmd->transfersize = blk_rq_bytes(req);
 	cmd->allowed = req->retries;
 	return BLKPREP_OK;
@@ -1203,6 +1196,13 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req)
 		goto out;
 	}
 
+	if (!blk_rq_bytes(req))
+		cmd->sc_data_direction = DMA_NONE;
+	else if (rq_data_dir(req) == WRITE)
+		cmd->sc_data_direction = DMA_TO_DEVICE;
+	else
+		cmd->sc_data_direction = DMA_FROM_DEVICE;
+
 	switch (req->cmd_type) {
 	case REQ_TYPE_FS:
 		ret = scsi_setup_fs_cmnd(sdev, req);

drivers/scsi/sd.c

@@ -994,14 +994,12 @@ static int sd_init_command(struct scsi_cmnd *SCpnt)
 			goto out;
 		}
 		SCpnt->cmnd[0] = WRITE_6;
-		SCpnt->sc_data_direction = DMA_TO_DEVICE;
 
 		if (blk_integrity_rq(rq))
 			sd_dif_prepare(rq, block, sdp->sector_size);
 
 	} else if (rq_data_dir(rq) == READ) {
 		SCpnt->cmnd[0] = READ_6;
-		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
 	} else {
 		scmd_printk(KERN_ERR, SCpnt, "Unknown command %llx\n", (unsigned long long) rq->cmd_flags);
 		goto out;

drivers/scsi/sr.c

@@ -438,11 +438,9 @@ static int sr_init_command(struct scsi_cmnd *SCpnt)
 		if (!cd->device->writeable)
 			goto out;
 		SCpnt->cmnd[0] = WRITE_10;
-		SCpnt->sc_data_direction = DMA_TO_DEVICE;
 		cd->cdi.media_written = 1;
 	} else if (rq_data_dir(rq) == READ) {
 		SCpnt->cmnd[0] = READ_10;
-		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
 	} else {
 		blk_dump_rq_flags(rq, "Unknown sr command");
 		goto out;