vhost: cleanup iterator update logic
Recent iterator-related changes in vhost made it
harder to follow the logic fixing up the header.
In fact, the fixup always happens at the same
offset: sizeof(virtio_net_hdr): sometimes the
fixup iterator is updated by copy_to_iter,
sometimes-by iov_iter_advance.
Rearrange code to make this obvious.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index afa06d2..ca70434 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -591,11 +591,6 @@
* TODO: support TSO.
*/
iov_iter_advance(&msg.msg_iter, vhost_hlen);
- } else {
- /* It'll come from socket; we'll need to patch
- * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF
- */
- iov_iter_advance(&fixup, sizeof(hdr));
}
err = sock->ops->recvmsg(NULL, sock, &msg,
sock_len, MSG_DONTWAIT | MSG_TRUNC);
@@ -609,11 +604,18 @@
continue;
}
/* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
- 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));
}
/* TODO: Should check and handle checksum. */