vhost: fix zcopy reference counting

Fix get/put refcount imbalance with zero copy,
which caused qemu to hang forever on guest driver unload.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 46822c0..c16d225 100644 (file)
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1578,7 +1578,6 @@ struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *vq,
        if (!ubufs)
                return ERR_PTR(-ENOMEM);
        kref_init(&ubufs->kref);
-       kref_get(&ubufs->kref);
        init_waitqueue_head(&ubufs->wait);
        ubufs->vq = vq;
        return ubufs;