Confusion about GstRTSPMountPoints

In gst-rtsp-server, a required code is as follows:

gst_rtsp_mount_points_add_factory (mounts, "/test", factory);

I traced the source code, as foliows:

void
gst_rtsp_mount_points_add_factory (GstRTSPMountPoints * mounts,
    const gchar * path, GstRTSPMediaFactory * factory)
{
  GstRTSPMountPointsPrivate *priv;
  DataItem *item;

  g_return_if_fail (GST_IS_RTSP_MOUNT_POINTS (mounts));
  g_return_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory));
  g_return_if_fail (path != NULL);

  priv = mounts->priv;

  item = data_item_new (g_strdup (path), strlen (path), factory);

  GST_INFO ("adding media factory %p for path %s", factory, path);

  g_mutex_lock (&priv->lock);
  g_sequence_append (priv->mounts, item);
  priv->dirty = TRUE;
  g_mutex_unlock (&priv->lock);
}

I am now confused, priv is a local variable, how does it carry on the subsequent push stream?