- if (unlikely(vhost_hlen) &&
- copy_to_iter(&hdr, sizeof(hdr), &fixup) != sizeof(hdr)) {
- vq_err(vq, "Unable to write vnet_hdr at addr %p\n",
- vq->iov->iov_base);
- break;
+ if (unlikely(vhost_hlen)) {
+ if (copy_to_iter(&hdr, sizeof(hdr),
+ &fixup) != sizeof(hdr)) {
+ vq_err(vq, "Unable to write vnet_hdr "
+ "at addr %p\n", vq->iov->iov_base);
+ break;
+ }
+ } else {
+ /* Header came from socket; we'll need to patch
+ * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF
+ */
+ iov_iter_advance(&fixup, sizeof(hdr));