ruct sock *sk, struct sock *newsk)
+{
+}
+
 static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
 {
 	return false;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 8dd7fbed5a942..46713b9ece063 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5024,6 +5024,19 @@ void mem_cgroup_sk_free(struct sock *sk)
 		css_put(&sk->sk_memcg->css);
 }
 
+void mem_cgroup_sk_inherit(const struct sock *sk, struct sock *newsk)
+{
+	if (sk->sk_memcg == newsk->sk_memcg)
+		return;
+
+	mem_cgroup_sk_free(newsk);
+
+	if (sk->sk_memcg)
+		css_get(&sk->sk_memcg->css);
+
+	newsk->sk_memcg = sk->sk_memcg;
+}
+
 /**
  * mem_cgroup_charge_skmem - charge socket memory
  * @memcg: memcg to charge
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index f31a3a79531a2..e8325890a3223 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1721,19 +1721,14 @@ static void mptcp_attach_cgroup(struct sock *parent, struct sock *child)
 	/* only the additional subflows created by kworkers have to be modified */
 	if (cgroup_id(sock_cgroup_ptr(parent_skcd)) !=
 	    cgroup_id(sock_cgroup_ptr(child_skcd))) {
-#ifdef CONFIG_MEMCG
-		struct mem_cgroup *memcg = parent->sk_memcg;
-
-		mem_cgroup_sk_free(child);
-		if (memcg && css_tryget(&memcg->css))
-			child->sk_memcg = memcg;
-#endif /* CONFIG_MEMCG */
-
 		cgroup_sk_free(child_skcd);
 		*child_skcd = *parent_skcd;
 		cgroup_sk_clone(child_skcd);
 	}
 #endif /* CONFIG_SOCK_CGROUP_DATA */
+
+	if (mem_cgroup_sockets_enabled)
+		mem_cgroup_sk_inherit(parent, child);
 }
 
 static void mptcp_subflow_ops_override(struct sock *ssk)
-- 
2.51.0[PATCH 6.17 251/563] mptcp: Fix up subflows memcg when CONFIG_SOCK_CGROUP_DATA=n.Greg Kroah-Hartman <gregkh@linuxfoundation.org> undefinedstable@vger.kernel.org undefined undefined undefined undefined undefined undefined undefined undefined¨