Am 15. Juni 2022 15:17:00 MESZ schrieb Christoph Hellwig <h...@lst.de>: >On Wed, Jun 15, 2022 at 02:15:33PM +0100, Robin Murphy wrote: >> Put simply, if you want to call dma_map_single() on a buffer, then that >> buffer needs to be allocated with kmalloc() (or technically alloc_pages(), >> but then dma_map_page() would make more sense when dealing with entire >> pages. > >Yes. It sounds like the memory here comes from the dma coherent >allocator, in which case the code need to use the address returned >by that and not create another mapping.
As i have not found position where memory is allocated (this is a very huge and dirty driver) is it maybe possible to check if buf is such "allready dma" memory (maybe is_vmalloc_addr) and call dma_single_map only if not (using original buf if yes)? But i guess it should map only a part of available (pre-allocated) memory and other parts of this are used somewhere else. So i can ran into some issues caused by sharing this full block in different functions. Hi, Thanks for first suggestions. regards Frank _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
