[PATCH] virtio-balloon: correct used length

[Jason Wang <jasowang@redhat.com>]

Spec said:

"and len the total of bytes written into the buffer."

For inflateq, deflateq and statsq, we don't process in_sg so the used
length should be zero. For free_page_vq, though the free pages are
supplied via in_sgs, zero used length should still be fine since
anyway driver is expected to use the length in this case and it
simplifies the error handling path.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/virtio-balloon.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index c6962fcbfe..3e52daa793 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -231,7 +231,7 @@ static void balloon_stats_poll_cb(void *opaque)
         return;
     }
 
-    virtqueue_push(s->svq, s->stats_vq_elem, s->stats_vq_offset);
+    virtqueue_push(s->svq, s->stats_vq_elem, 0);
     virtio_notify(vdev, s->svq);
     g_free(s->stats_vq_elem);
     s->stats_vq_elem = NULL;
@@ -438,7 +438,7 @@ static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
             memory_region_unref(section.mr);
         }
 
-        virtqueue_push(vq, elem, offset);
+        virtqueue_push(vq, elem, 0);
         virtio_notify(vdev, vq);
         g_free(elem);
         virtio_balloon_pbp_free(&pbp);
@@ -549,7 +549,7 @@ static bool get_free_page_hints(VirtIOBalloon *dev)
     }
 
 out:
-    virtqueue_push(vq, elem, 1);
+    virtqueue_push(vq, elem, 0);
     g_free(elem);
     return ret;
 }
-- 
2.25.1