Re: [PATCH v4 11/16] dma-mapping: export new dma_*map_phys() interface
From: Keith Busch <kbusch@kernel.org>
Date: 2025-08-19 18:22:34
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On Tue, Aug 19, 2025 at 08:36:55PM +0300, Leon Romanovsky wrote:
From: Leon Romanovsky <leonro@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@kernel.org>