Commit 9426ce47 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

mptcp: annotate lockless access for RX path fields 



The following fields:

 - ack_seq
 - snd_una
 - wnd_end
 - rmem_fwd_alloc

are protected by the data lock end accessed lockless in a few
spots. Ensure ONCE annotation for write (under such lock) and for
lockless read.

Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Reviewed-by: default avatarMat Martineau <martineau@kernel.org>
Signed-off-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d440a4e2

net/mptcp/options.c

+3 −3
Original line number Diff line number Diff line
@@ -1030,7 +1030,7 @@ u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq) 
static void __mptcp_snd_una_update(struct mptcp_sock *msk, u64 new_snd_una)

{

	msk->bytes_acked += new_snd_una - msk->snd_una;

	msk->snd_una = new_snd_una;

	WRITE_ONCE(msk->snd_una, new_snd_una);

}



static void ack_update_msk(struct mptcp_sock *msk,
@@ -1057,7 +1057,7 @@ static void ack_update_msk(struct mptcp_sock *msk, 
	new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd;



	if (after64(new_wnd_end, msk->wnd_end))

		msk->wnd_end = new_wnd_end;

		WRITE_ONCE(msk->wnd_end, new_wnd_end);



	/* this assumes mptcp_incoming_options() is invoked after tcp_ack() */

	if (after64(msk->wnd_end, snd_nxt))
@@ -1071,7 +1071,7 @@ static void ack_update_msk(struct mptcp_sock *msk, 


	trace_ack_update_msk(mp_opt->data_ack,

			     old_snd_una, new_snd_una,

			     new_wnd_end, msk->wnd_end);

			     new_wnd_end, READ_ONCE(msk->wnd_end));

}



bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit)

net/mptcp/protocol.c

+11 −8
Original line number Diff line number Diff line
@@ -410,6 +410,7 @@ static void mptcp_close_wake_up(struct sock *sk) 
		sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);

}



/* called under the msk socket lock */

static bool mptcp_pending_data_fin_ack(struct sock *sk)

{

	struct mptcp_sock *msk = mptcp_sk(sk);
@@ -441,16 +442,17 @@ static void mptcp_check_data_fin_ack(struct sock *sk) 
	}

}



/* can be called with no lock acquired */

static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)

{

	struct mptcp_sock *msk = mptcp_sk(sk);



	if (READ_ONCE(msk->rcv_data_fin) &&

	    ((1 << sk->sk_state) &

	    ((1 << inet_sk_state_load(sk)) &

	     (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {

		u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);



		if (msk->ack_seq == rcv_data_fin_seq) {

		if (READ_ONCE(msk->ack_seq) == rcv_data_fin_seq) {

			if (seq)

				*seq = rcv_data_fin_seq;
@@ -748,7 +750,7 @@ static bool __mptcp_ofo_queue(struct mptcp_sock *msk) 
			__skb_queue_tail(&sk->sk_receive_queue, skb);

		}

		msk->bytes_received += end_seq - msk->ack_seq;

		msk->ack_seq = end_seq;

		WRITE_ONCE(msk->ack_seq, end_seq);

		moved = true;

	}

	return moved;
@@ -985,6 +987,7 @@ static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag) 
	put_page(dfrag->page);

}



/* called under both the msk socket lock and the data lock */

static void __mptcp_clean_una(struct sock *sk)

{

	struct mptcp_sock *msk = mptcp_sk(sk);
@@ -2110,7 +2113,7 @@ static unsigned int mptcp_inq_hint(const struct sock *sk) 


	skb = skb_peek(&msk->receive_queue);

	if (skb) {

		u64 hint_val = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;

		u64 hint_val = READ_ONCE(msk->ack_seq) - MPTCP_SKB_CB(skb)->map_seq;



		if (hint_val >= INT_MAX)

			return INT_MAX;
@@ -2754,7 +2757,7 @@ static void __mptcp_init_sock(struct sock *sk) 
	__skb_queue_head_init(&msk->receive_queue);

	msk->out_of_order_queue = RB_ROOT;

	msk->first_pending = NULL;

	msk->rmem_fwd_alloc = 0;

	WRITE_ONCE(msk->rmem_fwd_alloc, 0);

	WRITE_ONCE(msk->rmem_released, 0);

	msk->timer_ival = TCP_RTO_MIN;

	msk->scaling_ratio = TCP_DEFAULT_SCALING_RATIO;
@@ -2970,7 +2973,7 @@ static void __mptcp_destroy_sock(struct sock *sk) 


	sk->sk_prot->destroy(sk);



	WARN_ON_ONCE(msk->rmem_fwd_alloc);

	WARN_ON_ONCE(READ_ONCE(msk->rmem_fwd_alloc));

	WARN_ON_ONCE(msk->rmem_released);

	sk_stream_kill_queues(sk);

	xfrm_sk_free_policy(sk);
@@ -3204,8 +3207,8 @@ struct sock *mptcp_sk_clone_init(const struct sock *sk, 


	WRITE_ONCE(msk->write_seq, subflow_req->idsn + 1);

	WRITE_ONCE(msk->snd_nxt, msk->write_seq);

	msk->snd_una = msk->write_seq;

	msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd;

	WRITE_ONCE(msk->snd_una, msk->write_seq);

	WRITE_ONCE(msk->wnd_end, msk->snd_nxt + req->rsk_rcv_wnd);

	msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;

	mptcp_init_sched(msk, mptcp_sk(sk)->sched);