[PATCH 2/9] block: add scatterlist-less DMA mapping helpers

[Christoph Hellwig]

On Thu, Jun 12, 2025 at 12:05:18PM +0530, Kanchan Joshi wrote:
> On 6/10/2025 10:36 AM, Christoph Hellwig wrote:
> > +static bool blk_dma_map_bus(struct request *req, struct device *dma_dev,
> 
> Both are not used in the function body.

I'll fix it.

> > + */
> > +bool blk_rq_dma_map_iter_start(struct request *req, struct device *dma_dev,
> > +		struct dma_iova_state *state, struct blk_dma_iter *iter)
> > +{
> > +	unsigned int total_len = blk_rq_payload_bytes(req);
> > +	struct phys_vec vec;
> > +
> > +	iter->iter.bio = req->bio;
> > +	iter->iter.iter = req->bio->bi_iter;
> > +	memset(&iter->p2pdma, 0, sizeof(iter->p2pdma));
> Should this (or maybe p2pdma field itself) be compiled out using 
> CONFIG_PCI_P2PDMA.

We could, but is it really worth the effort?