On 25.06.2025 15:18, Leon Romanovsky wrote:

This series refactors the DMA mapping to use physical addresses
as the primary interface instead of page+offset parameters. This
change aligns the DMA API with the underlying hardware reality where
DMA operations work with physical addresses, not page structures.

The series consists of 8 patches that progressively convert the DMA
mapping infrastructure from page-based to physical address-based APIs:

The series maintains backward compatibility by keeping the old
page-based API as wrapper functions around the new physical
address-based implementations.

Thanks for this rework! I assume that the next step is to add map_phys 
callback also to the dma_map_ops and teach various dma-mapping providers 
to use it to avoid more phys-to-page-to-phys conversions.

I only wonder if this newly introduced dma_map_phys()/dma_unmap_phys() 
API is also suitable for the recently discussed PCI P2P DMA? While 
adding a new API maybe we should take this into account? My main concern 
is the lack of the source phys addr passed to the dma_unmap_phys() 
function and I'm aware that this might complicate a bit code conversion 
from old dma_map/unmap_page() API.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland