1 files changed, 31 insertions, 8 deletions

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index d409586b5977..6ec245fd2778 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -346,10 +346,16 @@ struct mptcp_sock {
 		u64	rtt_us; /* last maximum rtt of subflows */
 	} rcvq_space;
 	u8		scaling_ratio;
+	bool		allow_subflows;
 
 	u32		subflow_id;
 	u32		setsockopt_seq;
 	char		ca_name[TCP_CA_NAME_MAX];
+
+	spinlock_t	fallback_lock;	/* protects fallback,
+					 * allow_infinite_fallback and
+					 * allow_join
+					 */
 };
 
 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock)
@@ -479,6 +485,7 @@ mptcp_subflow_rsk(const struct request_sock *rsk)
 
 struct mptcp_delegated_action {
 	struct napi_struct napi;
+	local_lock_t bh_lock;
 	struct list_head head;
 };
 
@@ -670,9 +677,11 @@ static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow,
 		if (WARN_ON_ONCE(!list_empty(&subflow->delegated_node)))
 			return;
 
+		local_lock_nested_bh(&mptcp_delegated_actions.bh_lock);
 		delegated = this_cpu_ptr(&mptcp_delegated_actions);
 		schedule = list_empty(&delegated->head);
 		list_add_tail(&subflow->delegated_node, &delegated->head);
+		local_unlock_nested_bh(&mptcp_delegated_actions.bh_lock);
 		sock_hold(mptcp_subflow_tcp_sock(subflow));
 		if (schedule)
 			napi_schedule(&delegated->napi);
@@ -684,11 +693,15 @@ mptcp_subflow_delegated_next(struct mptcp_delegated_action *delegated)
 {
 	struct mptcp_subflow_context *ret;
 
-	if (list_empty(&delegated->head))
+	local_lock_nested_bh(&mptcp_delegated_actions.bh_lock);
+	if (list_empty(&delegated->head)) {
+		local_unlock_nested_bh(&mptcp_delegated_actions.bh_lock);
 		return NULL;
+	}
 
 	ret = list_first_entry(&delegated->head, struct mptcp_subflow_context, delegated_node);
 	list_del_init(&ret->delegated_node);
+	local_unlock_nested_bh(&mptcp_delegated_actions.bh_lock);
 	return ret;
 }
 
@@ -744,6 +757,7 @@ void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
 			 struct sockaddr_storage *addr,
 			 unsigned short family);
 struct mptcp_sched_ops *mptcp_sched_find(const char *name);
+int mptcp_validate_scheduler(struct mptcp_sched_ops *sched);
 int mptcp_register_scheduler(struct mptcp_sched_ops *sched);
 void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched);
 void mptcp_sched_init(void);
@@ -1208,15 +1222,22 @@ static inline bool mptcp_check_fallback(const struct sock *sk)
 	return __mptcp_check_fallback(msk);
 }
 
-static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
+static inline bool __mptcp_try_fallback(struct mptcp_sock *msk)
 {
 	if (__mptcp_check_fallback(msk)) {
 		pr_debug("TCP fallback already done (msk=%p)\n", msk);
-		return;
+		return true;
 	}
-	if (WARN_ON_ONCE(!READ_ONCE(msk->allow_infinite_fallback)))
-		return;
+	spin_lock_bh(&msk->fallback_lock);
+	if (!msk->allow_infinite_fallback) {
+		spin_unlock_bh(&msk->fallback_lock);
+		return false;
+	}
+
+	msk->allow_subflows = false;
 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
+	spin_unlock_bh(&msk->fallback_lock);
+	return true;
 }
 
 static inline bool __mptcp_has_initial_subflow(const struct mptcp_sock *msk)
@@ -1228,14 +1249,15 @@ static inline bool __mptcp_has_initial_subflow(const struct mptcp_sock *msk)
 			TCPF_SYN_RECV | TCPF_LISTEN));
 }
 
-static inline void mptcp_do_fallback(struct sock *ssk)
+static inline bool mptcp_try_fallback(struct sock *ssk)
 {
 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
 	struct sock *sk = subflow->conn;
 	struct mptcp_sock *msk;
 
 	msk = mptcp_sk(sk);
-	__mptcp_do_fallback(msk);
+	if (!__mptcp_try_fallback(msk))
+		return false;
 	if (READ_ONCE(msk->snd_data_fin_enable) && !(ssk->sk_shutdown & SEND_SHUTDOWN)) {
 		gfp_t saved_allocation = ssk->sk_allocation;
 
@@ -1247,6 +1269,7 @@ static inline void mptcp_do_fallback(struct sock *ssk)
 		tcp_shutdown(ssk, SEND_SHUTDOWN);
 		ssk->sk_allocation = saved_allocation;
 	}
+	return true;
 }
 
 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)\n", __func__, a)
@@ -1256,7 +1279,7 @@ static inline void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
 {
 	pr_fallback(msk);
 	subflow->request_mptcp = 0;
-	__mptcp_do_fallback(msk);
+	WARN_ON_ONCE(!__mptcp_try_fallback(msk));
 }
 
 static inline bool mptcp_check_infinite_map(struct sk_buff *skb)