block: Fix bad data direction in SG_IO

Contrary to what the name misleads you to believe, SG_DXFER_TO_FROM_DEV
is really just a normal read seen from the device side.

This patch fixes http://lkml.org/lkml/2006/10/13/100

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

block/scsi_ioctl.c

@@ -246,10 +246,10 @@ static int sg_io(struct file *file, request_queue_t *q,
 		switch (hdr->dxfer_direction) {
 		default:
 			return -EINVAL;
-		case SG_DXFER_TO_FROM_DEV:
 		case SG_DXFER_TO_DEV:
 			writing = 1;
 			break;
+		case SG_DXFER_TO_FROM_DEV:
 		case SG_DXFER_FROM_DEV:
 			break;
 		}