On Tue, Apr 25, 2023 at 4:44 AM Andrey Smetanin
<asmetanin@xxxxxxxxxxxxxx> wrote:
>
> 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@xxxxxxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Thanks
> ---
> drivers/vhost/net.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 20265393aee7..0791fbdb3975 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -934,13 +934,18 @@ 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;
> --
> 2.25.1
>
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