[PATCH v9 52/96] mm/memcg: Add folio_uncharge_cgroup

["Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>]

Reimplement mem_cgroup_uncharge() as a wrapper around
folio_uncharge_cgroup().

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
 include/linux/memcontrol.h |  5 +++++
 mm/folio-compat.c          |  5 +++++
 mm/memcontrol.c            | 14 +++++++-------
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index d0798d54f637..2e68c9848432 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -700,6 +700,7 @@ static inline bool mem_cgroup_below_min(struct mem_cgroup *memcg)
 }
 
 int folio_charge_cgroup(struct folio *, struct mm_struct *, gfp_t);
+void folio_uncharge_cgroup(struct folio *);
 
 int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask);
 int mem_cgroup_swapin_charge_page(struct page *page, struct mm_struct *mm,
@@ -1209,6 +1210,10 @@ static inline int folio_charge_cgroup(struct folio *folio,
 	return 0;
 }
 
+static inline void folio_uncharge_cgroup(struct folio *)
+{
+}
+
 static inline int mem_cgroup_charge(struct page *page, struct mm_struct *mm,
 				    gfp_t gfp_mask)
 {
diff --git a/mm/folio-compat.c b/mm/folio-compat.c
index 1d71b8b587f8..d229b979b00d 100644
--- a/mm/folio-compat.c
+++ b/mm/folio-compat.c
@@ -54,4 +54,9 @@ int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp)
 {
 	return folio_charge_cgroup(page_folio(page), mm, gfp);
 }
+
+void mem_cgroup_uncharge(struct page *page)
+{
+	folio_uncharge_cgroup(page_folio(page));
+}
 #endif
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 529b10e72d5a..4ca2661cf891 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6717,24 +6717,24 @@ static void uncharge_page(struct page *page, struct uncharge_gather *ug)
 }
 
 /**
- * mem_cgroup_uncharge - uncharge a page
- * @page: page to uncharge
+ * folio_uncharge_cgroup - Uncharge a folio.
+ * @folio: Folio to uncharge.
  *
- * Uncharge a page previously charged with mem_cgroup_charge().
+ * Uncharge a folio previously charged with folio_charge_cgroup().
  */
-void mem_cgroup_uncharge(struct page *page)
+void folio_uncharge_cgroup(struct folio *folio)
 {
 	struct uncharge_gather ug;
 
 	if (mem_cgroup_disabled())
 		return;
 
-	/* Don't touch page->lru of any random page, pre-check: */
-	if (!page_memcg(page))
+	/* Don't touch folio->lru of any random page, pre-check: */
+	if (!folio_memcg(folio))
 		return;
 
 	uncharge_gather_clear(&ug);
-	uncharge_page(page, &ug);
+	uncharge_page(&folio->page, &ug);
 	uncharge_batch(&ug);
 }
 
-- 
2.30.2