On Thu, Jun 24, 2021 at 11:52:47AM +0200, Christian König wrote: > I've already converted a bunch of the GPU drivers, but there are at least 6 > GPU still needing to be fixed and on top of that comes VA-API and a few > others. > > What are your plans for the DMA mapping subsystem? Building a new API that allows batched DMA mapping without the scatterlist. The main input for my use case would be bio_vecs, but I plan to make it a little flexible, and the output would be a list of [dma_addr,len] tuples, with the API being flexible enough to just return a single [dma_addr,len] for the common IOMMU coalescing case. > >> Btw, one thing I noticed when looking over the dma-buf instances is that >> there is a lot of duplicated code for creating a sg_table from pages, >> and then mapping it. It would be good if we could move toward common >> helpers instead of duplicating that all over again. > > Can you give an example? Take a look at the get_sg_table and put_sg_table helpers in udmabuf. Those would also be useful in armda, i915, tegra, gntdev-dmabuf, mbochs in one form or another. Similar for variants that use a contigous regions.
