tree efa80f37e1046ae17172b1736b67c9f0b0aa5f23
parent 922659ea771b3fd728149262c5ea15608fab9719
author Christoph Hellwig <hch@lst.de> 1566811424 +0200
committer Christoph Hellwig <hch@lst.de> 1568198607 +0200

swiotlb-xen: use the same foreign page check everywhere

xen_dma_map_page uses a different and more complicated check for foreign
pages than the other three cache maintainance helpers.  Switch it to the
simpler pfn_valid method a well, and document the scheme with a single
improved comment in xen_dma_map_page.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>