[RFC PATCH v1 18/18] nvme-pci: use new dma API

Leon Romanovsky leon at kernel.org
Fri Jul 5 11:48:46 PDT 2024


On Fri, Jul 05, 2024 at 07:58:06AM +0200, Christoph Hellwig wrote:
> > This is exactly how dma_map_sg() works.
> 
> Which dma_map_sg?  swiotlb handling is implemented in the underlying
> ops, dma-direct and dma-iommu specifically.
> 
> dma-direct just iterates over the entries and calls dma_direct_map_page,
> which does a per-entry decision to bounce based on
> is_swiotlb_force_bounce, dma_capable and dma_kmalloc_needs_bounce.

dma-direct is not going to have "use_iova" flag. Robin pointed to
dma-iommu path.

In that case the flow is dma_map_sg()->iommu_dma_map_sg()->dev_use_sg_swiotlb().

Thanks

> 
> 



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