mm/hugetlb: convert demote_free_huge_page to folios

Change demote_free_huge_page to demote_free_hugetlb_folio() and change
demote_pool_huge_page() pass in a folio.

Link: https://lkml.kernel.org/r/20230113223057.173292-9-sidhartha.kumar@oracle.comSigned-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/hugetlb.c

@@ -3579,12 +3579,12 @@ static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
 	return 0;
 }
 
-static int demote_free_huge_page(struct hstate *h, struct page *page)
+static int demote_free_hugetlb_folio(struct hstate *h, struct folio *folio)
 {
-	int i, nid = page_to_nid(page);
+	int i, nid = folio_nid(folio);
 	struct hstate *target_hstate;
-	struct folio *folio = page_folio(page);
 	struct page *subpage;
+	struct folio *inner_folio;
 	int rc = 0;
 
 	target_hstate = size_to_hstate(PAGE_SIZE << h->demote_order);
@@ -3592,18 +3592,18 @@ static int demote_free_huge_page(struct hstate *h, struct page *page)
 	remove_hugetlb_folio_for_demote(h, folio, false);
 	spin_unlock_irq(&hugetlb_lock);
 
-	rc = hugetlb_vmemmap_restore(h, page);
+	rc = hugetlb_vmemmap_restore(h, &folio->page);
 	if (rc) {
-		/* Allocation of vmemmmap failed, we can not demote page */
+		/* Allocation of vmemmmap failed, we can not demote folio */
 		spin_lock_irq(&hugetlb_lock);
-		set_page_refcounted(page);
-		add_hugetlb_folio(h, page_folio(page), false);
+		folio_ref_unfreeze(folio, 1);
+		add_hugetlb_folio(h, folio, false);
 		return rc;
 	}
 
 	/*
 	 * Use destroy_compound_hugetlb_folio_for_demote for all huge page
-	 * sizes as it will not ref count pages.
+	 * sizes as it will not ref count folios.
 	 */
 	destroy_compound_hugetlb_folio_for_demote(folio, huge_page_order(h));
 
@@ -3618,15 +3618,15 @@ static int demote_free_huge_page(struct hstate *h, struct page *page)
 	mutex_lock(&target_hstate->resize_lock);
 	for (i = 0; i < pages_per_huge_page(h);
 				i += pages_per_huge_page(target_hstate)) {
-		subpage = nth_page(page, i);
-		folio = page_folio(subpage);
+		subpage = folio_page(folio, i);
+		inner_folio = page_folio(subpage);
 		if (hstate_is_gigantic(target_hstate))
-			prep_compound_gigantic_folio_for_demote(folio,
+			prep_compound_gigantic_folio_for_demote(inner_folio,
 							target_hstate->order);
 		else
 			prep_compound_page(subpage, target_hstate->order);
-		set_page_private(subpage, 0);
-		prep_new_hugetlb_folio(target_hstate, folio, nid);
+		folio_change_private(inner_folio, NULL);
+		prep_new_hugetlb_folio(target_hstate, inner_folio, nid);
 		free_huge_page(subpage);
 	}
 	mutex_unlock(&target_hstate->resize_lock);
@@ -3648,7 +3648,7 @@ static int demote_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
 	__must_hold(&hugetlb_lock)
 {
 	int nr_nodes, node;
-	struct page *page;
+	struct folio *folio;
 
 	lockdep_assert_held(&hugetlb_lock);
 
@@ -3659,11 +3659,10 @@ static int demote_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
 	}
 
 	for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
-		list_for_each_entry(page, &h->hugepage_freelists[node], lru) {
-			if (PageHWPoison(page))
+		list_for_each_entry(folio, &h->hugepage_freelists[node], lru) {
+			if (folio_test_hwpoison(folio))
 				continue;
-
-			return demote_free_huge_page(h, page);
+			return demote_free_hugetlb_folio(h, folio);
 		}
 	}