On 2021-07-16 12:33 a.m., Christoph Hellwig wrote:

On Thu, Jul 15, 2021 at 10:45:44AM -0600, Logan Gunthorpe wrote:

quoted

@@ -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?

Sure thing. All the feedback makes sense, we'll fix it up and send a v2
in due course.

Thanks,

Logan