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 <m...@redhat.com> --- drivers/vhost/net.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) 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 @@ static void handle_rx(struct vhost_net *net) * 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 @@ static void handle_rx(struct vhost_net *net) 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. */ -- MST -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/