1 files changed, 122 insertions, 63 deletions

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index f998a077c7dd..b9f16a1535d2 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -45,11 +45,14 @@ static struct percpu_counter mptcp_sockets_allocated;
 static void __mptcp_destroy_sock(struct sock *sk);
 static void __mptcp_check_send_data_fin(struct sock *sk);
 
+DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
+static struct net_device mptcp_napi_dev;
+
 /* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not
  * completed yet or has failed, return the subflow socket.
  * Otherwise return NULL.
  */
-static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
+struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
 {
 	if (!msk->subflow || READ_ONCE(msk->can_ack))
 		return NULL;
@@ -114,11 +117,7 @@ static int __mptcp_socket_create(struct mptcp_sock *msk)
 	list_add(&subflow->node, &msk->conn_list);
 	sock_hold(ssock->sk);
 	subflow->request_mptcp = 1;
-
-	/* accept() will wait on first subflow sk_wq, and we always wakes up
-	 * via msk->sk_socket
-	 */
-	RCU_INIT_POINTER(msk->first->sk_wq, &sk->sk_socket->wq);
+	mptcp_sock_graft(msk->first, sk->sk_socket);
 
 	return 0;
 }
@@ -734,10 +733,14 @@ wake:
 
 void __mptcp_flush_join_list(struct mptcp_sock *msk)
 {
+	struct mptcp_subflow_context *subflow;
+
 	if (likely(list_empty(&msk->join_list)))
 		return;
 
 	spin_lock_bh(&msk->join_list_lock);
+	list_for_each_entry(subflow, &msk->join_list, node)
+		mptcp_propagate_sndbuf((struct sock *)msk, mptcp_subflow_tcp_sock(subflow));
 	list_splice_tail_init(&msk->join_list, &msk->conn_list);
 	spin_unlock_bh(&msk->join_list_lock);
 }
@@ -1037,13 +1040,6 @@ out:
 			__mptcp_update_wmem(sk);
 			sk_mem_reclaim_partial(sk);
 		}
-
-		if (sk_stream_is_writeable(sk)) {
-			/* pairs with memory barrier in mptcp_poll */
-			smp_mb();
-			if (test_and_clear_bit(MPTCP_NOSPACE, &msk->flags))
-				sk_stream_write_space(sk);
-		}
 	}
 
 	if (snd_una == READ_ONCE(msk->snd_nxt)) {
@@ -1362,8 +1358,7 @@ struct subflow_send_info {
 	u64 ratio;
 };
 
-static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk,
-					   u32 *sndbuf)
+static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
 {
 	struct subflow_send_info send_info[2];
 	struct mptcp_subflow_context *subflow;
@@ -1374,24 +1369,17 @@ static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk,
 
 	sock_owned_by_me((struct sock *)msk);
 
-	*sndbuf = 0;
 	if (__mptcp_check_fallback(msk)) {
 		if (!msk->first)
 			return NULL;
-		*sndbuf = msk->first->sk_sndbuf;
 		return sk_stream_memory_free(msk->first) ? msk->first : NULL;
 	}
 
 	/* re-use last subflow, if the burst allow that */
 	if (msk->last_snd && msk->snd_burst > 0 &&
 	    sk_stream_memory_free(msk->last_snd) &&
-	    mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd))) {
-		mptcp_for_each_subflow(msk, subflow) {
-			ssk =  mptcp_subflow_tcp_sock(subflow);
-			*sndbuf = max(tcp_sk(ssk)->snd_wnd, *sndbuf);
-		}
+	    mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd)))
 		return msk->last_snd;
-	}
 
 	/* pick the subflow with the lower wmem/wspace ratio */
 	for (i = 0; i < 2; ++i) {
@@ -1404,8 +1392,7 @@ static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk,
 			continue;
 
 		nr_active += !subflow->backup;
-		*sndbuf = max(tcp_sk(ssk)->snd_wnd, *sndbuf);
-		if (!sk_stream_memory_free(subflow->tcp_sock))
+		if (!sk_stream_memory_free(subflow->tcp_sock) || !tcp_sk(ssk)->snd_wnd)
 			continue;
 
 		pace = READ_ONCE(ssk->sk_pacing_rate);
@@ -1431,9 +1418,10 @@ static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk,
 	if (send_info[0].ssk) {
 		msk->last_snd = send_info[0].ssk;
 		msk->snd_burst = min_t(int, MPTCP_SEND_BURST_SIZE,
-				       sk_stream_wspace(msk->last_snd));
+				       tcp_sk(msk->last_snd)->snd_wnd);
 		return msk->last_snd;
 	}
+
 	return NULL;
 }
 
@@ -1454,7 +1442,6 @@ static void mptcp_push_pending(struct sock *sk, unsigned int flags)
 	};
 	struct mptcp_data_frag *dfrag;
 	int len, copied = 0;
-	u32 sndbuf;
 
 	while ((dfrag = mptcp_send_head(sk))) {
 		info.sent = dfrag->already_sent;
@@ -1465,12 +1452,7 @@ static void mptcp_push_pending(struct sock *sk, unsigned int flags)
 
 			prev_ssk = ssk;
 			__mptcp_flush_join_list(msk);
-			ssk = mptcp_subflow_get_send(msk, &sndbuf);
-
-			/* do auto tuning */
-			if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK) &&
-			    sndbuf > READ_ONCE(sk->sk_sndbuf))
-				WRITE_ONCE(sk->sk_sndbuf, sndbuf);
+			ssk = mptcp_subflow_get_send(msk);
 
 			/* try to keep the subflow socket lock across
 			 * consecutive xmit on the same socket
@@ -1527,7 +1509,9 @@ static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk)
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	struct mptcp_sendmsg_info info;
 	struct mptcp_data_frag *dfrag;
+	struct sock *xmit_ssk;
 	int len, copied = 0;
+	bool first = true;
 
 	info.flags = 0;
 	while ((dfrag = mptcp_send_head(sk))) {
@@ -1537,10 +1521,17 @@ static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk)
 		while (len > 0) {
 			int ret = 0;
 
-			/* do auto tuning */
-			if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK) &&
-			    ssk->sk_sndbuf > READ_ONCE(sk->sk_sndbuf))
-				WRITE_ONCE(sk->sk_sndbuf, ssk->sk_sndbuf);
+			/* the caller already invoked the packet scheduler,
+			 * check for a different subflow usage only after
+			 * spooling the first chunk of data
+			 */
+			xmit_ssk = first ? ssk : mptcp_subflow_get_send(mptcp_sk(sk));
+			if (!xmit_ssk)
+				goto out;
+			if (xmit_ssk != ssk) {
+				mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk));
+				goto out;
+			}
 
 			if (unlikely(mptcp_must_reclaim_memory(sk, ssk))) {
 				__mptcp_update_wmem(sk);
@@ -1560,6 +1551,7 @@ static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk)
 			msk->tx_pending_data -= ret;
 			copied += ret;
 			len -= ret;
+			first = false;
 		}
 		WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
 	}
@@ -1579,6 +1571,15 @@ out:
 	}
 }
 
+static void mptcp_set_nospace(struct sock *sk)
+{
+	/* enable autotune */
+	set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+
+	/* will be cleared on avail space */
+	set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags);
+}
+
 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
@@ -1680,7 +1681,7 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		continue;
 
 wait_for_memory:
-		set_bit(MPTCP_NOSPACE, &msk->flags);
+		mptcp_set_nospace(sk);
 		mptcp_push_pending(sk, msg->msg_flags);
 		ret = sk_stream_wait_memory(sk, &timeo);
 		if (ret)
@@ -2116,9 +2117,6 @@ static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk)
 void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 		       struct mptcp_subflow_context *subflow)
 {
-	bool dispose_socket = false;
-	struct socket *sock;
-
 	list_del(&subflow->node);
 
 	lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
@@ -2126,11 +2124,8 @@ void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 	/* if we are invoked by the msk cleanup code, the subflow is
 	 * already orphaned
 	 */
-	sock = ssk->sk_socket;
-	if (sock) {
-		dispose_socket = sock != sk->sk_socket;
+	if (ssk->sk_socket)
 		sock_orphan(ssk);
-	}
 
 	subflow->disposable = 1;
 
@@ -2148,8 +2143,6 @@ void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 		__sock_put(ssk);
 	}
 	release_sock(ssk);
-	if (dispose_socket)
-		iput(SOCK_INODE(sock));
 
 	sock_put(ssk);
 }
@@ -2194,6 +2187,8 @@ static void __mptcp_close_subflow(struct mptcp_sock *msk)
 {
 	struct mptcp_subflow_context *subflow, *tmp;
 
+	might_sleep();
+
 	list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 
@@ -2536,6 +2531,14 @@ static void __mptcp_destroy_sock(struct sock *sk)
 
 	pr_debug("msk=%p", msk);
 
+	might_sleep();
+
+	/* dispose the ancillatory tcp socket, if any */
+	if (msk->subflow) {
+		iput(SOCK_INODE(msk->subflow));
+		msk->subflow = NULL;
+	}
+
 	/* be sure to always acquire the join list lock, to sync vs
 	 * mptcp_finish_join().
 	 */
@@ -2586,20 +2589,10 @@ cleanup:
 	inet_csk(sk)->icsk_mtup.probe_timestamp = tcp_jiffies32;
 	list_for_each_entry(subflow, &mptcp_sk(sk)->conn_list, node) {
 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
-		bool slow, dispose_socket;
-		struct socket *sock;
+		bool slow = lock_sock_fast(ssk);
 
-		slow = lock_sock_fast(ssk);
-		sock = ssk->sk_socket;
-		dispose_socket = sock && sock != sk->sk_socket;
 		sock_orphan(ssk);
 		unlock_sock_fast(ssk, slow);
-
-		/* for the outgoing subflows we additionally need to free
-		 * the associated socket
-		 */
-		if (dispose_socket)
-			iput(SOCK_INODE(sock));
 	}
 	sock_orphan(sk);
 
@@ -2928,10 +2921,16 @@ void __mptcp_check_push(struct sock *sk, struct sock *ssk)
 	if (!mptcp_send_head(sk))
 		return;
 
-	if (!sock_owned_by_user(sk))
-		__mptcp_subflow_push_pending(sk, ssk);
-	else
+	if (!sock_owned_by_user(sk)) {
+		struct sock *xmit_ssk = mptcp_subflow_get_send(mptcp_sk(sk));
+
+		if (xmit_ssk == ssk)
+			__mptcp_subflow_push_pending(sk, ssk);
+		else if (xmit_ssk)
+			mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk));
+	} else {
 		set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags);
+	}
 }
 
 #define MPTCP_DEFERRED_ALL (TCPF_WRITE_TIMER_DEFERRED)
@@ -2979,6 +2978,20 @@ static void mptcp_release_cb(struct sock *sk)
 	}
 }
 
+void mptcp_subflow_process_delegated(struct sock *ssk)
+{
+	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+	struct sock *sk = subflow->conn;
+
+	mptcp_data_lock(sk);
+	if (!sock_owned_by_user(sk))
+		__mptcp_subflow_push_pending(sk, ssk);
+	else
+		set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags);
+	mptcp_data_unlock(sk);
+	mptcp_subflow_delegated_done(subflow);
+}
+
 static int mptcp_hash(struct sock *sk)
 {
 	/* should never be called,
@@ -3041,7 +3054,7 @@ void mptcp_finish_connect(struct sock *ssk)
 	mptcp_rcv_space_init(msk, ssk);
 }
 
-static void mptcp_sock_graft(struct sock *sk, struct socket *parent)
+void mptcp_sock_graft(struct sock *sk, struct socket *parent)
 {
 	write_lock_bh(&sk->sk_callback_lock);
 	rcu_assign_pointer(sk->sk_wq, &parent->wq);
@@ -3284,6 +3297,7 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
 
 		mptcp_copy_inaddrs(newsk, msk->first);
 		mptcp_rcv_space_init(msk, msk->first);
+		mptcp_propagate_sndbuf(newsk, msk->first);
 
 		/* set ssk->sk_socket of accept()ed flows to mptcp socket.
 		 * This is needed so NOSPACE flag can be set from tcp stack.
@@ -3324,7 +3338,7 @@ static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
 	if (sk_stream_is_writeable(sk))
 		return EPOLLOUT | EPOLLWRNORM;
 
-	set_bit(MPTCP_NOSPACE, &msk->flags);
+	mptcp_set_nospace(sk);
 	smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */
 	if (sk_stream_is_writeable(sk))
 		return EPOLLOUT | EPOLLWRNORM;
@@ -3388,13 +3402,58 @@ static struct inet_protosw mptcp_protosw = {
 	.flags		= INET_PROTOSW_ICSK,
 };
 
+static int mptcp_napi_poll(struct napi_struct *napi, int budget)
+{
+	struct mptcp_delegated_action *delegated;
+	struct mptcp_subflow_context *subflow;
+	int work_done = 0;
+
+	delegated = container_of(napi, struct mptcp_delegated_action, napi);
+	while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) {
+		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+		bh_lock_sock_nested(ssk);
+		if (!sock_owned_by_user(ssk) &&
+		    mptcp_subflow_has_delegated_action(subflow))
+			mptcp_subflow_process_delegated(ssk);
+		/* ... elsewhere tcp_release_cb_override already processed
+		 * the action or will do at next release_sock().
+		 * In both case must dequeue the subflow here - on the same
+		 * CPU that scheduled it.
+		 */
+		bh_unlock_sock(ssk);
+		sock_put(ssk);
+
+		if (++work_done == budget)
+			return budget;
+	}
+
+	/* always provide a 0 'work_done' argument, so that napi_complete_done
+	 * will not try accessing the NULL napi->dev ptr
+	 */
+	napi_complete_done(napi, 0);
+	return work_done;
+}
+
 void __init mptcp_proto_init(void)
 {
+	struct mptcp_delegated_action *delegated;
+	int cpu;
+
 	mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
 
 	if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
 		panic("Failed to allocate MPTCP pcpu counter\n");
 
+	init_dummy_netdev(&mptcp_napi_dev);
+	for_each_possible_cpu(cpu) {
+		delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu);
+		INIT_LIST_HEAD(&delegated->head);
+		netif_tx_napi_add(&mptcp_napi_dev, &delegated->napi, mptcp_napi_poll,
+				  NAPI_POLL_WEIGHT);
+		napi_enable(&delegated->napi);
+	}
+
 	mptcp_subflow_init();
 	mptcp_pm_init();
 	mptcp_token_init();