[PATCH 2/9] mm/hugetlb_cgroup: convert hugetlb_cgroup_from_page() to folios

[Sidhartha Kumar <sidhartha.kumar@oracle.com>]

Introduce folios in __remove_hugetlb_page() by converting
hugetlb_cgroup_from_page() to use folios.

Also gets rid of unsed hugetlb_cgroup_from_page_resv() function.

Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
---
 include/linux/hugetlb_cgroup.h | 39 +++++++++++++++++-----------------
 mm/hugetlb.c                   |  5 +++--
 mm/hugetlb_cgroup.c            | 13 +++++++-----
 3 files changed, 31 insertions(+), 26 deletions(-)

diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h
index 7576e9ed8afe..feb2edafc8b6 100644
--- a/include/linux/hugetlb_cgroup.h
+++ b/include/linux/hugetlb_cgroup.h
@@ -67,27 +67,34 @@ struct hugetlb_cgroup {
 };
 
 static inline struct hugetlb_cgroup *
-__hugetlb_cgroup_from_page(struct page *page, bool rsvd)
+__hugetlb_cgroup_from_folio(struct folio *folio, bool rsvd)
 {
-	VM_BUG_ON_PAGE(!PageHuge(page), page);
+	struct page *tail;
 
-	if (compound_order(page) < HUGETLB_CGROUP_MIN_ORDER)
+	VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio);
+	if (folio_order(folio) < HUGETLB_CGROUP_MIN_ORDER)
 		return NULL;
-	if (rsvd)
-		return (void *)page_private(page + SUBPAGE_INDEX_CGROUP_RSVD);
-	else
-		return (void *)page_private(page + SUBPAGE_INDEX_CGROUP);
+
+	if (rsvd) {
+		tail = folio_page(folio, SUBPAGE_INDEX_CGROUP_RSVD);
+		return (void *)page_private(tail);
+	}
+
+	else {
+		tail = folio_page(folio, SUBPAGE_INDEX_CGROUP);
+		return (void *)page_private(tail);
+	}
 }
 
-static inline struct hugetlb_cgroup *hugetlb_cgroup_from_page(struct page *page)
+static inline struct hugetlb_cgroup *hugetlb_cgroup_from_folio(struct folio *folio)
 {
-	return __hugetlb_cgroup_from_page(page, false);
+	return __hugetlb_cgroup_from_folio(folio, false);
 }
 
 static inline struct hugetlb_cgroup *
-hugetlb_cgroup_from_page_rsvd(struct page *page)
+hugetlb_cgroup_from_folio_rsvd(struct folio *folio)
 {
-	return __hugetlb_cgroup_from_page(page, true);
+	return __hugetlb_cgroup_from_folio(folio, true);
 }
 
 static inline void __set_hugetlb_cgroup(struct folio *folio,
@@ -181,19 +188,13 @@ static inline void hugetlb_cgroup_uncharge_file_region(struct resv_map *resv,
 {
 }
 
-static inline struct hugetlb_cgroup *hugetlb_cgroup_from_page(struct page *page)
-{
-	return NULL;
-}
-
-static inline struct hugetlb_cgroup *
-hugetlb_cgroup_from_page_resv(struct page *page)
+static inline struct hugetlb_cgroup *hugetlb_cgroup_from_folio(struct folio *folio)
 {
 	return NULL;
 }
 
 static inline struct hugetlb_cgroup *
-hugetlb_cgroup_from_page_rsvd(struct page *page)
+hugetlb_cgroup_from_folio_rsvd(struct folio *folio)
 {
 	return NULL;
 }
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 4133ffbbeb50..bcb9bfce32ee 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1434,9 +1434,10 @@ static void __remove_hugetlb_page(struct hstate *h, struct page *page,
 							bool demote)
 {
 	int nid = page_to_nid(page);
+	struct folio *folio = page_folio(page);
 
-	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
-	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
+	VM_BUG_ON_FOLIO(hugetlb_cgroup_from_folio(folio), folio);
+	VM_BUG_ON_FOLIO(hugetlb_cgroup_from_folio_rsvd(folio), folio);
 
 	lockdep_assert_held(&hugetlb_lock);
 	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index 81675f8f44e9..600c98560a0f 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -191,8 +191,9 @@ static void hugetlb_cgroup_move_parent(int idx, struct hugetlb_cgroup *h_cg,
 	struct page_counter *counter;
 	struct hugetlb_cgroup *page_hcg;
 	struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(h_cg);
+	struct folio *folio = page_folio(page);
 
-	page_hcg = hugetlb_cgroup_from_page(page);
+	page_hcg = hugetlb_cgroup_from_folio(folio);
 	/*
 	 * We can have pages in active list without any cgroup
 	 * ie, hugepage with less than 3 pages. We can safely
@@ -352,14 +353,15 @@ static void __hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
 					   struct page *page, bool rsvd)
 {
 	struct hugetlb_cgroup *h_cg;
+	struct folio *folio = page_folio(page);
 
 	if (hugetlb_cgroup_disabled())
 		return;
 	lockdep_assert_held(&hugetlb_lock);
-	h_cg = __hugetlb_cgroup_from_page(page, rsvd);
+	h_cg = __hugetlb_cgroup_from_folio(folio, rsvd);
 	if (unlikely(!h_cg))
 		return;
-	__set_hugetlb_cgroup(page_folio(page), NULL, rsvd);
+	__set_hugetlb_cgroup(folio, NULL, rsvd);
 
 	page_counter_uncharge(__hugetlb_cgroup_counter_from_cgroup(h_cg, idx,
 								   rsvd),
@@ -891,13 +893,14 @@ void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
 	struct hugetlb_cgroup *h_cg;
 	struct hugetlb_cgroup *h_cg_rsvd;
 	struct hstate *h = page_hstate(oldhpage);
+	struct folio *old_folio = page_folio(oldhpage);
 
 	if (hugetlb_cgroup_disabled())
 		return;
 
 	spin_lock_irq(&hugetlb_lock);
-	h_cg = hugetlb_cgroup_from_page(oldhpage);
-	h_cg_rsvd = hugetlb_cgroup_from_page_rsvd(oldhpage);
+	h_cg = hugetlb_cgroup_from_folio(old_folio);
+	h_cg_rsvd = hugetlb_cgroup_from_folio_rsvd(old_folio);
 	set_hugetlb_cgroup(oldhpage, NULL);
 	set_hugetlb_cgroup_rsvd(oldhpage, NULL);
 
-- 
2.31.1