mm: mincore: remove special handling for VM_PFNMAP

As David pointed out, "it's hard to believe that someone depends on pages
in VM_PFNMAP to *not* be present", so remove the historical behavior that
always reports VM_PFNMAP pages as non-resident.

Adding mincore_pud_range() allows the page table walker to traverse the
full page table hierarchy without splitting a huge PUD, enabling much more
precise identification of resident pages in PFNMAP VMAs.

[wangkefeng.wang@huawei.com: address David's comments]
  Link: https://lore.kernel.org/20260720124151.1483820-1-wangkefeng.wang@huawei.com
Link: https://lore.kernel.org/linux-mm/0e619d71-1c3d-4534-8376-2982c7348c31@kernel.org/
Link: https://lore.kernel.org/20260717091347.1144789-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Suggested-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

0 files changed, 0 insertions, 0 deletions