This is another series that aims to fix issues with the balloon stats queue, heavily inspired by previous patches posted by Stefan and Roman.
Stefan Hajnoczi (1): virtio: add virtqueue_rewind() Ladi Prosek (2): virtio-balloon: discard virtqueue element on reset virtio-balloon: fix stats vq migration The first patch addresses the "inuse leak" issue which was discovered recently. The virtqueue_rewind() implementation is reposted verbatim. However, it is called from the set_status callback, same as in Roman's patch. Doing it in balloon_stats_poll_cb (Stefan's patch) is potentially problematic because the guest may push another buffer to the queue before the timer fires, so we could still leak a virtqueue slot. Also, we want to call the full-blown virtio_balloon_receive_stats and not manually reconstruct only some pieces of the state. It is not necessary to check balloon_stats_supported. Pushing buffers without negotiating stats support would be a driver bug. The common codepath does not check it either.
