BugLink: https://bugs.launchpad.net/bugs/1811080

Extracted from commit cde70140 "mm/gup: Overload get_user_pages()
functions".  This is needed before picking commit 768ae309
"mm: replace get_user_pages() write/force parameters with gup_flags".
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>