> I'm totally not following this argument. This has nothing to do with IOMMU > or not. If you have an IOMMU, the dma code will know where the pages are > anyway, so it can always map them into user space. The dma code might > have an easier way to do it other than follwoing the page tables. > Ah. Sorry for that. I mixed dma_alloc_* up with dma_map_*. I identified the reason why mmap_* in dma_map_ops is required. You mean that nothing but DMA API knows what pages will be mapped to user space. Thanks anyway. KyongHo. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>