proc: convert smaps_pmd_entry to use a folio

Replace two calls to compound_head() with one.

Link: https://lkml.kernel.org/r/20240403171456.1445117-5-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/proc/task_mmu.c

@@ -578,6 +578,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 	struct vm_area_struct *vma = walk->vma;
 	bool locked = !!(vma->vm_flags & VM_LOCKED);
 	struct page *page = NULL;
+	struct folio *folio;
 	bool migration = false;
 
 	if (pmd_present(*pmd)) {
@@ -592,11 +593,12 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 	}
 	if (IS_ERR_OR_NULL(page))
 		return;
-	if (PageAnon(page))
+	folio = page_folio(page);
+	if (folio_test_anon(folio))
 		mss->anonymous_thp += HPAGE_PMD_SIZE;
-	else if (PageSwapBacked(page))
+	else if (folio_test_swapbacked(folio))
 		mss->shmem_thp += HPAGE_PMD_SIZE;
-	else if (is_zone_device_page(page))
+	else if (folio_is_zone_device(folio))
 		/* pass */;
 	else
 		mss->file_thp += HPAGE_PMD_SIZE;