vhost: don't bother with copying iovec in handle_tx()
just advance the msg.msg_iter and be done with that.
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: kvm@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 6906f76..d86cc9b 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -336,7 +336,7 @@
{
struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
struct vhost_virtqueue *vq = &nvq->vq;
- unsigned out, in, s;
+ unsigned out, in;
int head;
struct msghdr msg = {
.msg_name = NULL,
@@ -395,16 +395,17 @@
break;
}
/* Skip header. TODO: support TSO. */
- s = move_iovec_hdr(vq->iov, nvq->hdr, hdr_size, out);
len = iov_length(vq->iov, out);
iov_iter_init(&msg.msg_iter, WRITE, vq->iov, out, len);
+ iov_iter_advance(&msg.msg_iter, hdr_size);
/* Sanity check */
- if (!len) {
+ if (!iov_iter_count(&msg.msg_iter)) {
vq_err(vq, "Unexpected header len for TX: "
"%zd expected %zd\n",
- iov_length(nvq->hdr, s), hdr_size);
+ len, hdr_size);
break;
}
+ len = iov_iter_count(&msg.msg_iter);
zcopy_used = zcopy && len >= VHOST_GOODCOPY_LEN
&& (nvq->upend_idx + 1) % UIO_MAXIOV !=