On Thu, Jul 15, 2021 at 10:45:44AM -0600, Logan Gunthorpe wrote: > @@ -194,6 +194,8 @@ static int __dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, > else > ents = ops->map_sg(dev, sg, nents, dir, attrs); > > + WARN_ON_ONCE(ents == 0); Turns this into a negative error code while we're at it, just to keep the callers sane?