mm/hugetlb: convert hugetlb prep functions to folios

Convert prep_new_huge_page() and __prep_compound_gigantic_page() to
folios.

Link: https://lkml.kernel.org/r/20221129225039.82257-10-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Tarun Sahu <tsahu@linux.ibm.com>
Cc: Wei Chen <harperchen1110@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/hugetlb.c

@@ -1789,29 +1789,27 @@ static void __prep_new_hugetlb_folio(struct hstate *h, struct folio *folio)
 	set_hugetlb_cgroup_rsvd(folio, NULL);
 }
 
-static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
+static void prep_new_hugetlb_folio(struct hstate *h, struct folio *folio, int nid)
 {
-	struct folio *folio = page_folio(page);
-
 	__prep_new_hugetlb_folio(h, folio);
 	spin_lock_irq(&hugetlb_lock);
 	__prep_account_new_huge_page(h, nid);
 	spin_unlock_irq(&hugetlb_lock);
 }
 
-static bool __prep_compound_gigantic_page(struct page *page, unsigned int order,
-								bool demote)
+static bool __prep_compound_gigantic_folio(struct folio *folio,
+					unsigned int order, bool demote)
 {
 	int i, j;
 	int nr_pages = 1 << order;
 	struct page *p;
 
-	/* we rely on prep_new_huge_page to set the destructor */
-	set_compound_order(page, order);
-	__ClearPageReserved(page);
-	__SetPageHead(page);
+	/* we rely on prep_new_hugetlb_folio to set the destructor */
+	folio_set_compound_order(folio, order);
+	__folio_clear_reserved(folio);
+	__folio_set_head(folio);
 	for (i = 0; i < nr_pages; i++) {
-		p = nth_page(page, i);
+		p = folio_page(folio, i);
 
 		/*
 		 * For gigantic hugepages allocated through bootmem at
@@ -1853,43 +1851,41 @@ static bool __prep_compound_gigantic_page(struct page *page, unsigned int order,
 			VM_BUG_ON_PAGE(page_count(p), p);
 		}
 		if (i != 0)
-			set_compound_head(p, page);
+			set_compound_head(p, &folio->page);
 	}
-	atomic_set(compound_mapcount_ptr(page), -1);
-	atomic_set(subpages_mapcount_ptr(page), 0);
-	atomic_set(compound_pincount_ptr(page), 0);
+	atomic_set(folio_mapcount_ptr(folio), -1);
+	atomic_set(folio_subpages_mapcount_ptr(folio), 0);
+	atomic_set(folio_pincount_ptr(folio), 0);
 	return true;
 
 out_error:
 	/* undo page modifications made above */
 	for (j = 0; j < i; j++) {
-		p = nth_page(page, j);
+		p = folio_page(folio, j);
 		if (j != 0)
 			clear_compound_head(p);
 		set_page_refcounted(p);
 	}
 	/* need to clear PG_reserved on remaining tail pages  */
 	for (; j < nr_pages; j++) {
-		p = nth_page(page, j);
+		p = folio_page(folio, j);
 		__ClearPageReserved(p);
 	}
-	set_compound_order(page, 0);
-#ifdef CONFIG_64BIT
-	page[1].compound_nr = 0;
-#endif
-	__ClearPageHead(page);
+	folio_set_compound_order(folio, 0);
+	__folio_clear_head(folio);
 	return false;
 }
 
-static bool prep_compound_gigantic_page(struct page *page, unsigned int order)
+static bool prep_compound_gigantic_folio(struct folio *folio,
+							unsigned int order)
 {
-	return __prep_compound_gigantic_page(page, order, false);
+	return __prep_compound_gigantic_folio(folio, order, false);
 }
 
-static bool prep_compound_gigantic_page_for_demote(struct page *page,
+static bool prep_compound_gigantic_folio_for_demote(struct folio *folio,
 							unsigned int order)
 {
-	return __prep_compound_gigantic_page(page, order, true);
+	return __prep_compound_gigantic_folio(folio, order, true);
 }
 
 /*
@@ -2041,7 +2037,7 @@ static struct page *alloc_fresh_huge_page(struct hstate *h,
 		return NULL;
 	folio = page_folio(page);
 	if (hstate_is_gigantic(h)) {
-		if (!prep_compound_gigantic_page(page, huge_page_order(h))) {
+		if (!prep_compound_gigantic_folio(folio, huge_page_order(h))) {
 			/*
 			 * Rare failure to convert pages to compound page.
 			 * Free pages and try again - ONCE!
@@ -2054,7 +2050,7 @@ static struct page *alloc_fresh_huge_page(struct hstate *h,
 			return NULL;
 		}
 	}
-	prep_new_huge_page(h, page, page_to_nid(page));
+	prep_new_hugetlb_folio(h, folio, folio_nid(folio));
 
 	return page;
 }
@@ -3058,10 +3054,10 @@ static void __init gather_bootmem_prealloc(void)
 		struct hstate *h = m->hstate;
 
 		VM_BUG_ON(!hstate_is_gigantic(h));
-		WARN_ON(page_count(page) != 1);
-		if (prep_compound_gigantic_page(page, huge_page_order(h))) {
-			WARN_ON(PageReserved(page));
-			prep_new_huge_page(h, page, page_to_nid(page));
+		WARN_ON(folio_ref_count(folio) != 1);
+		if (prep_compound_gigantic_folio(folio, huge_page_order(h))) {
+			WARN_ON(folio_test_reserved(folio));
+			prep_new_hugetlb_folio(h, folio, folio_nid(folio));
 			free_huge_page(page); /* add to the hugepage allocator */
 		} else {
 			/* VERY unlikely inflated ref count on a tail page */
@@ -3480,13 +3476,14 @@ static int demote_free_huge_page(struct hstate *h, struct page *page)
 	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);
 		if (hstate_is_gigantic(target_hstate))
-			prep_compound_gigantic_page_for_demote(subpage,
+			prep_compound_gigantic_folio_for_demote(folio,
 							target_hstate->order);
 		else
 			prep_compound_page(subpage, target_hstate->order);
 		set_page_private(subpage, 0);
-		prep_new_huge_page(target_hstate, subpage, nid);
+		prep_new_hugetlb_folio(target_hstate, folio, nid);
 		free_huge_page(subpage);
 	}
 	mutex_unlock(&target_hstate->resize_lock);