xen-swiotlb vs phys_to_dma

[Christoph Hellwig <hch@xxxxxx>]

Hi Stefano,

I've looked over xen-swiotlb in linux-next, that is with your recent
changes to take dma offsets into account.  One thing that puzzles me
is that xen_swiotlb_map_page passes virt_to_phys(xen_io_tlb_start) as
the tbl_dma_addr argument to swiotlb_tbl_map_single, despite the fact
that the argument is a dma_addr_t and both other callers translate
from a physical to the dma address.  Was this an oversight?