Re: [PATCH 1/2] dma-mapping: prepare dma_map_ops to conversion to physical address

[Leon Romanovsky <leon@kernel.org>]

On Thu, Jul 17, 2025 at 10:44:35AM -0300, Jason Gunthorpe wrote:
> On Thu, Jul 17, 2025 at 09:47:09AM +0300, Leon Romanovsky wrote:
> 
> > @@ -183,7 +187,11 @@ dma_addr_t dma_map_phys(struct device *dev, phys_addr_t phys, size_t size,
> >  		 * All platforms which implement .map_page() don't support
> >  		 * non-struct page backed addresses.
> >  		 */
> > -		addr = ops->map_page(dev, page, offset, size, dir, attrs);
> > +		if (ops->map_phys)
> > +			addr = ops->map_phys(dev, phys, size, dir, attrs);
> > +		if (ops->map_page)
> > +			addr = ops->map_page(dev, page, offset, size, dir,
> > +					     attrs);
> 
> I would expect 'else if'

I don't expect both of them to exist. There is WARN_ON_ONCE() to catch it.
If it is important, I can add else.

> 
> > @@ -213,8 +221,16 @@ void dma_unmap_phys(struct device *dev, dma_addr_t addr, size_t size,
> >  		dma_direct_unmap_phys(dev, addr, size, dir, attrs);
> >  	else if (use_dma_iommu(dev))
> >  		iommu_dma_unmap_phys(dev, addr, size, dir, attrs);
> > -	else
> > -		ops->unmap_page(dev, addr, size, dir, attrs);
> > +	else {
> > +		if (IS_ENABLED(CONFIG_DMA_API_DEBUG))
> > +			/* We shouldn't have both functions */
> > +			WARN_ON_ONCE(ops->unmap_page && ops->unmap_phys);
> > +
> > +		if (ops->unmap_phys)
> > +			ops->unmap_phys(dev, addr, size, dir, attrs);
> > +		if (ops->unmap_page)
> > +			ops->unmap_page(dev, addr, size, dir, attrs);
> 
> Here too
> 
> What is the practical difference between unmap_phys and unmap_page?

There is no difference. It is provided to provide symmetrical interface
to .map_phys, simple rename.

Thanks