s390/hugetlb: Convert PG_arch_1 code to work on folio->flags

Let's make it clearer that we are always working on folio flags and
never page flags of tail pages by converting remaining PG_arch_1 users
that modify page->flags to modify folio->flags instead.

No functional change intended, because we would always have worked with
the head page (where page->flags corresponds to folio->flags) and never
with tail pages.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20240508182955.358628-11-david@redhat.comSigned-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

arch/s390/mm/gmap.c

@@ -2733,7 +2733,7 @@ static int __s390_enable_skey_hugetlb(pte_t *pte, unsigned long addr,
 {
 	pmd_t *pmd = (pmd_t *)pte;
 	unsigned long start, end;
-	struct page *page = pmd_page(*pmd);
+	struct folio *folio = page_folio(pmd_page(*pmd));
 
 	/*
 	 * The write check makes sure we do not set a key on shared
@@ -2748,7 +2748,7 @@ static int __s390_enable_skey_hugetlb(pte_t *pte, unsigned long addr,
 	start = pmd_val(*pmd) & HPAGE_MASK;
 	end = start + HPAGE_SIZE;
 	__storage_key_init_range(start, end);
-	set_bit(PG_arch_1, &page->flags);
+	set_bit(PG_arch_1, &folio->flags);
 	cond_resched();
 	return 0;
 }

arch/s390/mm/hugetlbpage.c

@@ -121,7 +121,7 @@ static inline pte_t __rste_to_pte(unsigned long rste)
 
 static void clear_huge_pte_skeys(struct mm_struct *mm, unsigned long rste)
 {
-	struct page *page;
+	struct folio *folio;
 	unsigned long size, paddr;
 
 	if (!mm_uses_skeys(mm) ||
@@ -129,16 +129,16 @@ static void clear_huge_pte_skeys(struct mm_struct *mm, unsigned long rste)
 		return;
 
 	if ((rste & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) {
-		page = pud_page(__pud(rste));
+		folio = page_folio(pud_page(__pud(rste)));
 		size = PUD_SIZE;
 		paddr = rste & PUD_MASK;
 	} else {
-		page = pmd_page(__pmd(rste));
+		folio = page_folio(pmd_page(__pmd(rste)));
 		size = PMD_SIZE;
 		paddr = rste & PMD_MASK;
 	}
 
-	if (!test_and_set_bit(PG_arch_1, &page->flags))
+	if (!test_and_set_bit(PG_arch_1, &folio->flags))
 		__storage_key_init_range(paddr, paddr + size);
 }