Merge tag 'dma-mapping-4.17-3' of git://git.infradead.org/users/hch/dma-mapping

Merge tag 'dma-mapping-4.17-3' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping fixes from Christoph Hellwig:
 "A few small dma-mapping fixes for Linux 4.17-rc3:

   - don't loop to try GFP_DMA allocations if ZONE_DMA is not actually
     enabled (regression in 4.16)

   - don't try to do virt_to_page before we know we actuall have a valid
     page in dma_common_mmap

   - a comment fixup related to the above fix"

* tag 'dma-mapping-4.17-3' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: postpone cpu addr translation on mmap
  dma-coherent: clarify dma_mmap_from_dev_coherent documentation
  dma-direct: don't retry allocation for no-op GFP_DMA