[PATCH v3 0/3] mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes

[David Hildenbrand]

Based on mm/mm-unstable.

While working on improving vm_normal_page() and friends, I stumbled
over this issues: refcounted "normal" folios must not be marked
using pmd_special() / pud_special(). Otherwise, we're effectively telling
the system that these folios are no "normal", violating the rules we
documented for vm_normal_page().

Fortunately, there are not many pmd_special()/pud_special() users yet.
So far there doesn't seem to be serious damage.

Tested using the ndctl tests ("ndctl:dax" suite).

v2 -> v3:
* Added tags (thanks for all the review!)
* Smaller fixups (add empty lines) and patch description improvements

v1 -> v2:
* "mm/huge_memory: don't ignore queried cachemode in vmf_insert_pfn_pud()"
 -> Added after stumbling over that
* Modified the other tests to reuse the existing function by passing a
  new struct
* Renamed the patches to talk about "folios" instead of pages and adjusted
  the patch descriptions
* Dropped RB/TB from Dan and Oscar due to the changes

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Nico Pache <npache@xxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Dev Jain <dev.jain@xxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>

David Hildenbrand (3):
  mm/huge_memory: don't ignore queried cachemode in vmf_insert_pfn_pud()
  mm/huge_memory: don't mark refcounted folios special in
    vmf_insert_folio_pmd()
  mm/huge_memory: don't mark refcounted folios special in
    vmf_insert_folio_pud()

 include/linux/mm.h |  19 +++++++-
 mm/huge_memory.c   | 112 ++++++++++++++++++++++++++++-----------------
 2 files changed, 87 insertions(+), 44 deletions(-)

-- 
2.49.0