mm: fail get_vaddr_frames() for filesystem-dax mappings

mm: fail get_vaddr_frames() for filesystem-dax mappings

Until there is a solution to the dma-to-dax vs truncate problem it is
not safe to allow V4L2, Exynos, and other frame vector users to create
long standing / irrevocable memory registrations against filesytem-dax
vmas.

[[email protected]: add comment for vma_is_fsdax() check in get_vaddr_frames(), per Jan]
Link: http://lkml.kernel.org/r/151197874035.26211.4061781453123083667.stgit@dwillia2-desk3.amr.corp.intel.com
Link: http://lkml.kernel.org/r/151068939985.7446.15684639617389154187.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings")
Signed-off-by: Dan Williams <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: Seung-Woo Kim <[email protected]>
Cc: Joonyoung Shim <[email protected]>
Cc: Kyungmin Park <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Doug Ledford <[email protected]>
Cc: Hal Rosenstock <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jeff Moyer <[email protected]>
Cc: Ross Zwisler <[email protected]>
Cc: Sean Hefty <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>