[PATCH] mm/vmpressure: replace vmpressure_to_css() with vmpressure_to_memcg()

[Hui Su]

We can get memcg directly form vmpr instead of vmpr->memcg->css->memcg,
so add a new func helper vmpressure_to_memcg().
And no code will use vmpressure_to_css(), so delete it.

Signed-off-by: Hui Su <suhui@xxxxxxxx>
---
 include/linux/vmpressure.h | 2 +-
 mm/memcontrol.c            | 4 ++--
 mm/vmpressure.c            | 3 +--
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/include/linux/vmpressure.h b/include/linux/vmpressure.h
index 6d28bc433c1c..6a2f51ebbfd3 100644
--- a/include/linux/vmpressure.h
+++ b/include/linux/vmpressure.h
@@ -37,7 +37,7 @@ extern void vmpressure_prio(gfp_t gfp, struct mem_cgroup *memcg, int prio);
 extern void vmpressure_init(struct vmpressure *vmpr);
 extern void vmpressure_cleanup(struct vmpressure *vmpr);
 extern struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg);
-extern struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr);
+extern struct mem_cgroup *vmpressure_to_memcg(struct vmpressure *vmpr);
 extern int vmpressure_register_event(struct mem_cgroup *memcg,
 				     struct eventfd_ctx *eventfd,
 				     const char *args);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 64ada9e650a5..62163a9cee63 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -247,9 +247,9 @@ struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
 	return &memcg->vmpressure;
 }
 
-struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
+struct mem_cgroup *vmpressure_to_memcg(struct vmpressure *vmpr)
 {
-	return &container_of(vmpr, struct mem_cgroup, vmpressure)->css;
+	return container_of(vmpr, struct mem_cgroup, vmpressure);
 }
 
 #ifdef CONFIG_MEMCG_KMEM
diff --git a/mm/vmpressure.c b/mm/vmpressure.c
index d69019fc3789..04e81ac6d5d8 100644
--- a/mm/vmpressure.c
+++ b/mm/vmpressure.c
@@ -74,8 +74,7 @@ static struct vmpressure *work_to_vmpressure(struct work_struct *work)
 
 static struct vmpressure *vmpressure_parent(struct vmpressure *vmpr)
 {
-	struct cgroup_subsys_state *css = vmpressure_to_css(vmpr);
-	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+	struct mem_cgroup *memcg = vmpressure_to_memcg(vmpr);
 
 	memcg = parent_mem_cgroup(memcg);
 	if (!memcg)
-- 
2.25.1