[PATCH v2 05/10] scsi: virtio_scsi: Drop DID_NEXUS_FAILURE use

[Mike Christie <michael.christie@oracle.com>]

DID_NEXUS_FAILURE is internal to the SCSI layer. Drivers must not use it
because:

1. It's not propagated upwards, so SG IO/passthrough users will not see an
error and think a command was successful.

2. There is no handling for them in scsi_decide_disposition so it results
in the scsi eh running.

It looks like virtio_scsi gets this when something like qemu returns
VIRTIO_SCSI_S_NEXUS_FAILURE. It looks like qemu returns that error code
if host OS returns DID_NEXUS_FAILURE (qemu's internal
SCSI_HOST_RESERVATION_ERROR maps to DID_NEXUS_FAILURE). This shouldn't
happen for linux since we don't propagate that error code to userspace.

This has us convert VIRTIO_SCSI_S_NEXUS_FAILURE to a
SAM_STAT_RESERVATION_CONFLICT in case some other virt layer is returning
it. In that case we will still get the reservation confict failure we
expect.

Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
 drivers/scsi/virtio_scsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 112d8c3962b0..00cf6743db8c 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -144,7 +144,7 @@ static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
 		set_host_byte(sc, DID_BAD_TARGET);
 		break;
 	case VIRTIO_SCSI_S_NEXUS_FAILURE:
-		set_host_byte(sc, DID_NEXUS_FAILURE);
+		set_status_byte(sc, SAM_STAT_RESERVATION_CONFLICT);
 		break;
 	default:
 		scmd_printk(KERN_WARNING, sc, "Unknown response %d",
-- 
2.18.2