From: Jason Wang Date: Fri, 25 Sep 2015 13:21:29 +0800 Subject: [PATCH] virtio: introduce virtqueue_discard() This patch introduces virtqueue_discard() to discard a descriptor and unmap the sgs. This will be used by the patch that will discard descriptor when packet is truncated. Cc: Michael S. Tsirkin Signed-off-by: Jason Wang Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin (cherry picked from commit 29b9f5efd78ae0f9cc02dd169b6e80d2c404bade) --- hw/virtio/virtio.c | 7 +++++++ include/hw/virtio/virtio.h | 2 ++ 2 files changed, 9 insertions(+) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 7d88f26..e9f72a5 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -263,6 +263,13 @@ static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem, 0, elem->out_sg[i].iov_len); } +void virtqueue_discard(VirtQueue *vq, const VirtQueueElement *elem, + unsigned int len) +{ + vq->last_avail_idx--; + virtqueue_unmap_sg(vq, elem, len); +} + void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem, unsigned int len, unsigned int idx) { diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index d95f8b6..1899654 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -136,6 +136,8 @@ void virtio_del_queue(VirtIODevice *vdev, int n); void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem, unsigned int len); void virtqueue_flush(VirtQueue *vq, unsigned int count); +void virtqueue_discard(VirtQueue *vq, const VirtQueueElement *elem, + unsigned int len); void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem, unsigned int len, unsigned int idx);