Re: [PATCH crypto 2/2] crypto: safexcel - Map AEAD buffers with accurate DMA directions

[Herbert Xu <herbert@gondor.apana.org.au>]

On Tue, Sep 15, 2026 at 01:32:12PM +0200, Ralf Lici wrote:
>
> +static int safexcel_map_aead(struct device *dev, struct scatterlist *sgl,
> +			     int nents, unsigned int output_offset,
> +			     unsigned int output_len, bool inplace)
> +{
> +	struct scatterlist *sg;
> +	unsigned int offset = 0;
> +	int i;
> +
> +	for_each_sg(sgl, sg, nents, i) {
> +		enum dma_data_direction dir;
> +
> +		dir = safexcel_aead_dma_dir(offset, sg->length, output_offset,
> +					    output_len, inplace);
> +		sg_dma_address(sg) = dma_map_page(dev, sg_page(sg), sg->offset,
> +						  sg->length, dir);
> +		if (dma_mapping_error(dev, sg_dma_address(sg)))
> +			goto err_unmap;
> +		sg_dma_len(sg) = sg->length;
> +		offset += sg->length;
> +	}
> +
> +	return nents;
> +
> +err_unmap:
> +	safexcel_unmap_aead(dev, sgl, i, output_offset, output_len, inplace);
> +	return 0;
> +}

Is this assuming that the SG list actually contains one entry for
each type of data? What if the input is completely linear, i.e.,
the AD, cipher and tag are all described by a single SG entry?

In IPsec this is often the case.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt