proc: convert clear_refs_pte_range to use a folio

Patch series "Remove page_idle and page_young wrappers".

There are only a couple of places left using the page wrappers for idle &
young tracking.  Convert the two users in proc and then we can remove the
wrappers.  That enables the further simplification of autogenerating the
definitions when CONFIG_PAGE_IDLE_FLAG is disabled.  


This patch (of 4):

Replaces four calls to compound_head() with two.

Link: https://lkml.kernel.org/r/20240402201252.917342-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20240402201252.917342-2-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>

fs/proc/task_mmu.c

@@ -1161,7 +1161,7 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
 	struct vm_area_struct *vma = walk->vma;
 	pte_t *pte, ptent;
 	spinlock_t *ptl;
-	struct page *page;
+	struct folio *folio;
 
 	ptl = pmd_trans_huge_lock(pmd, vma);
 	if (ptl) {
@@ -1173,12 +1173,12 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
 		if (!pmd_present(*pmd))
 			goto out;
 
-		page = pmd_page(*pmd);
+		folio = pmd_folio(*pmd);
 
 		/* Clear accessed and referenced bits. */
 		pmdp_test_and_clear_young(vma, addr, pmd);
-		test_and_clear_page_young(page);
-		ClearPageReferenced(page);
+		folio_test_clear_young(folio);
+		folio_clear_referenced(folio);
 out:
 		spin_unlock(ptl);
 		return 0;
@@ -1200,14 +1200,14 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
 		if (!pte_present(ptent))
 			continue;
 
-		page = vm_normal_page(vma, addr, ptent);
-		if (!page)
+		folio = vm_normal_folio(vma, addr, ptent);
+		if (!folio)
 			continue;
 
 		/* Clear accessed and referenced bits. */
 		ptep_test_and_clear_young(vma, addr, pte);
-		test_and_clear_page_young(page);
-		ClearPageReferenced(page);
+		folio_test_clear_young(folio);
+		folio_clear_referenced(folio);
 	}
 	pte_unmap_unlock(pte - 1, ptl);
 	cond_resched();