[PATCH v4 11/16] dma-mapping: export new dma_*map_phys() interface

[Keith Busch]

On Tue, Aug 19, 2025 at 08:36:55PM +0300, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro at nvidia.com>
> 
> Introduce new DMA mapping functions dma_map_phys() and dma_unmap_phys()
> that operate directly on physical addresses instead of page+offset
> parameters. This provides a more efficient interface for drivers that
> already have physical addresses available.
> 
> The new functions are implemented as the primary mapping layer, with
> the existing dma_map_page_attrs()/dma_map_resource() and
> dma_unmap_page_attrs()/dma_unmap_resource() functions converted to simple
> wrappers around the phys-based implementations.
> 
> In case dma_map_page_attrs(), the struct page is converted to physical
> address with help of page_to_phys() function and dma_map_resource()
> provides physical address as is together with addition of DMA_ATTR_MMIO
> attribute.
> 
> The old page-based API is preserved in mapping.c to ensure that existing
> code won't be affected by changing EXPORT_SYMBOL to EXPORT_SYMBOL_GPL
> variant for dma_*map_phys().

Looks good.

Reviewed-by: Keith Busch <kbusch at kernel.org>