mm/hotplug: prepare shrink_{zone, pgdat}_span for sub-section removal

Sub-section hotplug support reduces the unit of operation of hotplug
from section-sized-units (PAGES_PER_SECTION) to sub-section-sized units
(PAGES_PER_SUBSECTION).  Teach shrink_{zone,pgdat}_span() to consider
PAGES_PER_SUBSECTION boundaries as the points where pfn_valid(), not
valid_section(), can toggle.

[[email protected]: fix shrink_{zone,node}_span]
  Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/156092351496.979959.12703722803097017492.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <[email protected]>
Signed-off-by: Oscar Salvador <[email protected]>
Reviewed-by: Pavel Tatashin <[email protected]>
Reviewed-by: Oscar Salvador <[email protected]>
Tested-by: Aneesh Kumar K.V <[email protected]>	[ppc64]
Cc: Michal Hocko <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Logan Gunthorpe <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Jane Chu <[email protected]>
Cc: Jeff Moyer <[email protected]>
Cc: Jérôme Glisse <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Toshi Kani <[email protected]>
Cc: Wei Yang <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions