ieee1394: sbp2: fix rescan-scsi-bus

rescan-scsi-bus used to add SBP-2 targets which weren't there.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

drivers/ieee1394/sbp2.c

@@ -1974,6 +1974,9 @@ static int sbp2scsi_slave_alloc(struct scsi_device *sdev)
 {
 	struct sbp2_lu *lu = (struct sbp2_lu *)sdev->host->hostdata[0];
 
+	if (sdev->lun != 0 || sdev->id != lu->ud->id || sdev->channel != 0)
+		return -ENODEV;
+
 	lu->sdev = sdev;
 	sdev->allow_restart = 1;