Re: [PATCH net-next v1 5/5] virtio_ring: enable packed ring

[Tiwei Bie <tiwei.bie@intel.com>]

On Tue, Jul 10, 2018 at 01:51:20PM +0800, Jason Wang wrote:
> On 2018年07月09日 15:22, Tiwei Bie wrote:
> > Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> > ---
> >   drivers/s390/virtio/virtio_ccw.c | 8 ++++++++
> >   drivers/virtio/virtio_ring.c     | 2 ++
> >   2 files changed, 10 insertions(+)
> > 
> > diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
> > index 8f5c1d7f751a..ff5b85736d8d 100644
> > --- a/drivers/s390/virtio/virtio_ccw.c
> > +++ b/drivers/s390/virtio/virtio_ccw.c
> > @@ -765,6 +765,11 @@ static u64 virtio_ccw_get_features(struct virtio_device *vdev)
> >   	return rc;
> >   }
> > +static void ccw_transport_features(struct virtio_device *vdev)
> > +{
> > +	__virtio_clear_bit(vdev, VIRTIO_F_RING_PACKED);
> > +}
> 
> I think we need a better comment to explain why it was disabled here.

Yeah, I'll do it!

Best regards,
Tiwei Bie

> 
> Thanks
> 
> > +
> >   static int virtio_ccw_finalize_features(struct virtio_device *vdev)
> >   {
> >   	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
> > @@ -791,6 +796,9 @@ static int virtio_ccw_finalize_features(struct virtio_device *vdev)
> >   	/* Give virtio_ring a chance to accept features. */
> >   	vring_transport_features(vdev);
> > +	/* Give virtio_ccw a chance to accept features. */
> > +	ccw_transport_features(vdev);
> > +
> >   	features->index = 0;
> >   	features->features = cpu_to_le32((u32)vdev->features);
> >   	/* Write the first half of the feature bits to the host. */
> > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > index 4b3f9e1a3cab..64f20023f088 100644
> > --- a/drivers/virtio/virtio_ring.c
> > +++ b/drivers/virtio/virtio_ring.c
> > @@ -1968,6 +1968,8 @@ void vring_transport_features(struct virtio_device *vdev)
> >   			break;
> >   		case VIRTIO_F_IOMMU_PLATFORM:
> >   			break;
> > +		case VIRTIO_F_RING_PACKED:
> > +			break;
> >   		default:
> >   			/* We don't understand this bit. */
> >   			__virtio_clear_bit(vdev, i);
>