Subject: Re: [PATCH v2 01/21] dma-mapping: Allow map_sg() ops to return negative error codes

From: Christoph Hellwig <[email-masked]>
Date: Sun, 25 Jul 2021 08:07:47 +0200

> +int dma_map_sgtable(struct device *dev, struct sg_table *sgt,
> +		    enum dma_data_direction dir, unsigned long attrs)
> +{
> +	int nents;
> +
> +	nents = __dma_map_sg_attrs(dev, sgt->sgl, sgt->orig_nents, dir, attrs);
> +	if (nents == 0)
> +		return -EIO;
> +	else if (nents < 0) {
> +		if (WARN_ON_ONCE(nents != -EINVAL && nents != -ENOMEM &&
> +				 nents != -EIO))
> +			return -EIO;

I think this validation of the errnos needs to go into __dma_map_sg_attrs,
so that we catch it for the classic dma_map_sg callers as well.