On Wed, Jul 22, 2026 at 04:57:09PM -0300, Jason Gunthorpe wrote:
> On Tue, Jul 21, 2026 at 03:40:56PM +0300, Leon Romanovsky wrote:
>
> > Why don't we continue the effort to remove "struct page" entirely
> > from the DMA API internals?
> >
> > IMHO, everything not exposed to DMA API users should use
> > phys_addr_t, including the DMA address pool.
>
> The alloc interfaces return a struct page, that is why this stuff is
> organized like this. Look at dma_alloc_pages()
And I didn't say that we should change dma_alloc_pages(). It is external
API, which needs to be struct *page. I'm talking about internals.
Even dma_alloc_pages() flow shows how convoluted and non-uniform
the code underneath which performs translations all the time.
dma_alloc_pages()
-> __dma_alloc_pages()
-> dma_direct_alloc_pages()
....
ret = page_address(page); <--- here we need virt address
if (dma_set_decrypted(dev, ret, size))
goto out_leak_pages;
memset(ret, 0, size);
*dma_handle = phys_to_dma_direct(dev, page_to_phys(page)); <- and here
we need phys address
return page;
So my point is that internal flows should not require struct page
and should not depend on it.
>
> There is also an API that forms a scatterlist that has to be struct
> page as well
>
> Jason
>
