Re: [FIXUP v11] fixup! s390: vfio-ap: implement mediated device open callback

Cornelia Huck
2018-09-28T13:46:47Z

On Fri, 28 Sep 2018 15:42:35 +0200
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> On 09/28/2018 03:41 PM, Halil Pasic wrote:
> >
> >
> > On 09/28/2018 03:35 PM, Cornelia Huck wrote:
> >> On Fri, 28 Sep 2018 09:33:21 -0400
> >> Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote:
> >>
> >>> From: Tony Krowiak <akrowiak@linux.ibm.com>
> >>>
> >>> Fixes case statement in vfio_ap_mdev_copy_masks() function in
> >>> vfio-ap-ops.c.
> >>> ---
> >>> drivers/s390/crypto/vfio_ap_ops.c | 3 ++-
> >>> 1 file changed, 2 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> >>> index e1e1beaaeba5..86b42487a51c 100644
> >>> --- a/drivers/s390/crypto/vfio_ap_ops.c
> >>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> >>> @@ -741,11 +741,12 @@ static void vfio_ap_mdev_copy_masks(struct ap_matrix_mdev *matrix_mdev)
> >>> break;
> >>> case CRYCB_FORMAT1:
> >>> case CRYCB_FORMAT0:
> >>> - default:
> >>> apm = (unsigned long *)crycb->apcb0.apm;
> >>> aqm = (unsigned long *)crycb->apcb0.aqm;
> >>> adm = (unsigned long *)crycb->apcb0.adm;
> >>> break;
> >>> + default:
> >>> + return;
> >>
> >> /* cannot happen */
> >>
> >> ?
> >
> > Or use something like BUG(). Without conveying that default is illegal we
> > don't gain anything over the previous version IMHO.
>
> Only WARN_ON, if at all.

Agreed.

This is only a marker for some future developer who might need to deal
with a new format.