On Mon, Nov 27, 2017 at 8:15 AM, Jan Kara <j...@suse.cz> wrote: > On Tue 14-11-17 11:56:39, Dan Williams wrote: >> 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. >> >> Cc: Inki Dae <inki....@samsung.com> >> Cc: Seung-Woo Kim <sw0312....@samsung.com> >> Cc: Joonyoung Shim <jy0922.s...@samsung.com> >> Cc: Kyungmin Park <kyungmin.p...@samsung.com> >> Cc: Mauro Carvalho Chehab <mche...@kernel.org> >> Cc: linux-media@vger.kernel.org >> Cc: Jan Kara <j...@suse.cz> >> Cc: Mel Gorman <mgor...@suse.de> >> Cc: Vlastimil Babka <vba...@suse.cz> >> Cc: Andrew Morton <a...@linux-foundation.org> >> Cc: <sta...@vger.kernel.org> >> Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings") >> Signed-off-by: Dan Williams <dan.j.willi...@intel.com> > > Makes sense. I'd just note that in principle get_vaddr_frames() is no more > long-term than get_user_pages(). It is just so that all the users of > get_vaddr_frames() currently want a long-term reference. Maybe could you > add here also a comment that the vma_is_fsdax() check is there because all > users of this function want a long term page reference? With that you can > add:
Ok, will do. > Reviewed-by: Jan Kara <j...@suse.cz> Thanks.