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Commit 6ac705b1 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: remove tcp_ecn_make_synack() socket argument 



SYNACK packets might be sent without holding socket lock.

For DCTCP/ECN sake, we should call INET_ECN_xmit() while
socket lock is owned, and only when we init/change congestion control.

This also fixies a bug if congestion module is changed from
dctcp to another one on a listener : we now clear ECN bits
properly.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 37bfbdda

net/ipv4/tcp_cong.c

+10 −2
Original line number Diff line number Diff line
@@ -173,6 +173,10 @@ void tcp_assign_congestion_control(struct sock *sk) 
	 */

	if (ca->get_info)

		memset(icsk->icsk_ca_priv, 0, sizeof(icsk->icsk_ca_priv));

	if (ca->flags & TCP_CONG_NEEDS_ECN)

		INET_ECN_xmit(sk);

	else

		INET_ECN_dontxmit(sk);

}



void tcp_init_congestion_control(struct sock *sk)
@@ -181,6 +185,10 @@ void tcp_init_congestion_control(struct sock *sk) 


	if (icsk->icsk_ca_ops->init)

		icsk->icsk_ca_ops->init(sk);

	if (tcp_ca_needs_ecn(sk))

		INET_ECN_xmit(sk);

	else

		INET_ECN_dontxmit(sk);

}



static void tcp_reinit_congestion_control(struct sock *sk,
@@ -192,8 +200,8 @@ static void tcp_reinit_congestion_control(struct sock *sk, 
	icsk->icsk_ca_ops = ca;

	icsk->icsk_ca_setsockopt = 1;



	if (sk->sk_state != TCP_CLOSE && icsk->icsk_ca_ops->init)

		icsk->icsk_ca_ops->init(sk);

	if (sk->sk_state != TCP_CLOSE)

		tcp_init_congestion_control(sk);

}



/* Manage refcounts on socket close. */

net/ipv4/tcp_output.c

+3 −7
Original line number Diff line number Diff line
@@ -357,14 +357,10 @@ static void tcp_ecn_clear_syn(struct sock *sk, struct sk_buff *skb) 
}



static void

tcp_ecn_make_synack(const struct request_sock *req, struct tcphdr *th,

		    struct sock *sk)

tcp_ecn_make_synack(const struct request_sock *req, struct tcphdr *th)

{

	if (inet_rsk(req)->ecn_ok) {

	if (inet_rsk(req)->ecn_ok)

		th->ece = 1;

		if (tcp_ca_needs_ecn(sk))

			INET_ECN_xmit(sk);

	}

}



/* Set up ECN state for a packet on a ESTABLISHED socket that is about to
@@ -2998,7 +2994,7 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst, 
	memset(th, 0, sizeof(struct tcphdr));

	th->syn = 1;

	th->ack = 1;

	tcp_ecn_make_synack(req, th, sk);

	tcp_ecn_make_synack(req, th);

	th->source = htons(ireq->ir_num);

	th->dest = ireq->ir_rmt_port;

	/* Setting of flags are superfluous here for callers (and ECE is