[PATCH net-next v2 5/5] virtio_ring: enable packed ring

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

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
---
 drivers/s390/virtio/virtio_ccw.c | 14 ++++++++++++++
 drivers/virtio/virtio_ring.c     |  2 ++
 2 files changed, 16 insertions(+)

diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 8f5c1d7f751a..8654f3a94635 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -765,6 +765,17 @@ static u64 virtio_ccw_get_features(struct virtio_device *vdev)
 	return rc;
 }
 
+static void ccw_transport_features(struct virtio_device *vdev)
+{
+	/*
+	 * Packed ring isn't enabled on virtio_ccw for now,
+	 * because virtio_ccw uses some legacy accessors,
+	 * e.g. virtqueue_get_avail() and virtqueue_get_used()
+	 * which aren't available in packed ring currently.
+	 */
+	__virtio_clear_bit(vdev, VIRTIO_F_RING_PACKED);
+}
+
 static int virtio_ccw_finalize_features(struct virtio_device *vdev)
 {
 	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
@@ -791,6 +802,9 @@ 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 f79a1e17f7d1..807ed4b362c5 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);
-- 
2.18.0