vhost_net: revert upend_idx only on retriable error

Fix possible virtqueue used buffers leak and corresponding stuck
in case of temporary -EIO from sendmsg() which is produced by
tun driver while backend device is not up.

In case of no-retriable error and zcopy do not revert upend_idx
to pass packet data (that is update used_idx in corresponding
vhost_zerocopy_signal_used()) as if packet data has been
transferred successfully.

v2: set vq->heads[ubuf->desc].len equal to VHOST_DMA_DONE_LEN
in case of fake successful transmit.

Signed-off-by: Andrey Smetanin <asmetanin@yandex-team.ru>
Message-Id: <20230424204411.24888-1-asmetanin@yandex-team.ru>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Andrey Smetanin <asmetanin@yandex-team.ru>
Acked-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Andrey Smetanin 2023-04-24 23:44:11 +03:00 committed by Michael S. Tsirkin
parent 376daf3177
commit 1f5d2e3bab

View File

@ -935,13 +935,18 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
err = sock->ops->sendmsg(sock, &msg, len);
if (unlikely(err < 0)) {
bool retry = err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS;
if (zcopy_used) {
if (vq->heads[ubuf->desc].len == VHOST_DMA_IN_PROGRESS)
vhost_net_ubuf_put(ubufs);
nvq->upend_idx = ((unsigned)nvq->upend_idx - 1)
% UIO_MAXIOV;
if (retry)
nvq->upend_idx = ((unsigned)nvq->upend_idx - 1)
% UIO_MAXIOV;
else
vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN;
}
if (err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS) {
if (retry) {
vhost_discard_vq_desc(vq, 1);
vhost_net_enable_vq(net, vq);
break;