scsi: virtio_scsi: Do not overwrite SCSI status

When a sense code is present we should not override the SAM status; the
driver already sets it based on the response from the hypervisor.

In addition we should only copy the sense buffer if one is actually
provided by the hypervisor.

Link: https://lore.kernel.org/r/20210622091153.29231-1-hare@suse.de
Fixes: 464a00c ("scsi: core: Kill DRIVER_SENSE")
Tested-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/virtio_scsi.c

@@ -156,12 +156,11 @@ static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
 
 	WARN_ON(virtio32_to_cpu(vscsi->vdev, resp->sense_len) >
 		VIRTIO_SCSI_SENSE_SIZE);
-	if (sc->sense_buffer) {
+	if (resp->sense_len) {
 		memcpy(sc->sense_buffer, resp->sense,
 		       min_t(u32,
 			     virtio32_to_cpu(vscsi->vdev, resp->sense_len),
 			     VIRTIO_SCSI_SENSE_SIZE));
-		set_status_byte(sc, SAM_STAT_CHECK_CONDITION);
 	}
 
 	sc->scsi_done(sc);