mm: convert do_huge_pmd_anonymous_page to huge_zero_folio

Use folios more widely.

Link: https://lkml.kernel.org/r/20240326202833.523759-7-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/huge_memory.c

@@ -971,14 +971,14 @@ gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma)
 }
 
 /* Caller must hold page table lock. */
-static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
+static void set_huge_zero_folio(pgtable_t pgtable, struct mm_struct *mm,
 		struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd,
-		struct page *zero_page)
+		struct folio *zero_folio)
 {
 	pmd_t entry;
 	if (!pmd_none(*pmd))
 		return;
-	entry = mk_pmd(zero_page, vma->vm_page_prot);
+	entry = mk_pmd(&zero_folio->page, vma->vm_page_prot);
 	entry = pmd_mkhuge(entry);
 	pgtable_trans_huge_deposit(mm, pmd, pgtable);
 	set_pmd_at(mm, haddr, pmd, entry);
@@ -1002,13 +1002,14 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf)
 			!mm_forbids_zeropage(vma->vm_mm) &&
 			transparent_hugepage_use_zero_page()) {
 		pgtable_t pgtable;
-		struct page *zero_page;
+		struct folio *zero_folio;
 		vm_fault_t ret;
+
 		pgtable = pte_alloc_one(vma->vm_mm);
 		if (unlikely(!pgtable))
 			return VM_FAULT_OOM;
-		zero_page = mm_get_huge_zero_page(vma->vm_mm);
-		if (unlikely(!zero_page)) {
+		zero_folio = mm_get_huge_zero_folio(vma->vm_mm);
+		if (unlikely(!zero_folio)) {
 			pte_free(vma->vm_mm, pgtable);
 			count_vm_event(THP_FAULT_FALLBACK);
 			return VM_FAULT_FALLBACK;
@@ -1026,8 +1027,8 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf)
 				ret = handle_userfault(vmf, VM_UFFD_MISSING);
 				VM_BUG_ON(ret & VM_FAULT_FALLBACK);
 			} else {
-				set_huge_zero_page(pgtable, vma->vm_mm, vma,
-						   haddr, vmf->pmd, zero_page);
+				set_huge_zero_folio(pgtable, vma->vm_mm, vma,
+						   haddr, vmf->pmd, zero_folio);
 				update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
 				spin_unlock(vmf->ptl);
 			}
@@ -1336,9 +1337,9 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 	 */
 	if (is_huge_zero_pmd(pmd)) {
 		/*
-		 * get_huge_zero_page() will never allocate a new page here,
-		 * since we already have a zero page to copy. It just takes a
-		 * reference.
+		 * mm_get_huge_zero_folio() will never allocate a new
+		 * folio here, since we already have a zero page to
+		 * copy. It just takes a reference.
 		 */
 		mm_get_huge_zero_folio(dst_mm);
 		goto out_zero_page;