[PATCH RFC 06/14] mm/huge_memory: support huge zero folio in vmf_insert_folio_pmd()

[David Hildenbrand]

Just like we do for vmf_insert_page_mkwrite() -> ... ->
insert_page_into_pte_locked(), support the huge zero folio.

Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
 mm/huge_memory.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1ea23900b5adb..92400f3baa9ff 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1418,9 +1418,11 @@ static vm_fault_t insert_pmd(struct vm_area_struct *vma, unsigned long addr,
 	if (fop.is_folio) {
 		entry = folio_mk_pmd(fop.folio, vma->vm_page_prot);
 
-		folio_get(fop.folio);
-		folio_add_file_rmap_pmd(fop.folio, &fop.folio->page, vma);
-		add_mm_counter(mm, mm_counter_file(fop.folio), HPAGE_PMD_NR);
+		if (!is_huge_zero_folio(fop.folio)) {
+			folio_get(fop.folio);
+			folio_add_file_rmap_pmd(fop.folio, &fop.folio->page, vma);
+			add_mm_counter(mm, mm_counter_file(fop.folio), HPAGE_PMD_NR);
+		}
 	} else {
 		entry = pmd_mkhuge(pfn_pmd(fop.pfn, prot));
 		entry = pmd_mkspecial(entry);
-- 
2.49.0