Commit cabeccbd authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

tcp: kill eff_sacks "cache", the sole user can calculate itself 



Also fixes insignificant bug that would cause sending of stale
SACK block (would occur in some corner cases).

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 758ce5c8

include/linux/tcp.h

+0 −1
Original line number Diff line number Diff line
@@ -218,7 +218,6 @@ struct tcp_options_received { 
		snd_wscale : 4,	/* Window scaling received from sender	*/

		rcv_wscale : 4;	/* Window scaling to send to receiver	*/

/*	SACKs data	*/

	u8	eff_sacks;	/* Size of SACK array to send with next packet */

	u8	num_sacks;	/* Number of SACK blocks		*/

	u16	user_mss;  	/* mss requested by user in ioctl */

	u16	mss_clamp;	/* Maximal mss, negotiated at connection setup */

include/net/tcp.h

+0 −1
Original line number Diff line number Diff line
@@ -926,7 +926,6 @@ extern void tcp_done(struct sock *sk); 
static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)

{

	rx_opt->dsack = 0;

	rx_opt->eff_sacks = 0;

	rx_opt->num_sacks = 0;

}

net/ipv4/tcp_input.c

+2 −13
Original line number Diff line number Diff line
@@ -4099,7 +4099,6 @@ static void tcp_dsack_set(struct sock *sk, u32 seq, u32 end_seq) 
		tp->rx_opt.dsack = 1;

		tp->duplicate_sack[0].start_seq = seq;

		tp->duplicate_sack[0].end_seq = end_seq;

		tp->rx_opt.eff_sacks = tp->rx_opt.num_sacks + 1;

	}

}
@@ -4154,8 +4153,6 @@ static void tcp_sack_maybe_coalesce(struct tcp_sock *tp) 
			 * Decrease num_sacks.

			 */

			tp->rx_opt.num_sacks--;

			tp->rx_opt.eff_sacks = tp->rx_opt.num_sacks +

					       tp->rx_opt.dsack;

			for (i = this_sack; i < tp->rx_opt.num_sacks; i++)

				sp[i] = sp[i + 1];

			continue;
@@ -4218,7 +4215,6 @@ static void tcp_sack_new_ofo_skb(struct sock *sk, u32 seq, u32 end_seq) 
	sp->start_seq = seq;

	sp->end_seq = end_seq;

	tp->rx_opt.num_sacks++;

	tp->rx_opt.eff_sacks = tp->rx_opt.num_sacks + tp->rx_opt.dsack;

}



/* RCV.NXT advances, some SACKs should be eaten. */
@@ -4232,7 +4228,6 @@ static void tcp_sack_remove(struct tcp_sock *tp) 
	/* Empty ofo queue, hence, all the SACKs are eaten. Clear. */

	if (skb_queue_empty(&tp->out_of_order_queue)) {

		tp->rx_opt.num_sacks = 0;

		tp->rx_opt.eff_sacks = tp->rx_opt.dsack;

		return;

	}
@@ -4253,11 +4248,8 @@ static void tcp_sack_remove(struct tcp_sock *tp) 
		this_sack++;

		sp++;

	}

	if (num_sacks != tp->rx_opt.num_sacks) {

	if (num_sacks != tp->rx_opt.num_sacks)

		tp->rx_opt.num_sacks = num_sacks;

		tp->rx_opt.eff_sacks = tp->rx_opt.num_sacks +

				       tp->rx_opt.dsack;

	}

}



/* This one checks to see if we can put data from the
@@ -4333,10 +4325,8 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) 


	TCP_ECN_accept_cwr(tp, skb);



	if (tp->rx_opt.dsack) {

	if (tp->rx_opt.dsack)

		tp->rx_opt.dsack = 0;

		tp->rx_opt.eff_sacks = tp->rx_opt.num_sacks;

	}



	/*  Queue data for delivery to the user.

	 *  Packets in sequence go to the receive queue.
@@ -4456,7 +4446,6 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) 
		if (tcp_is_sack(tp)) {

			tp->rx_opt.num_sacks = 1;

			tp->rx_opt.dsack     = 0;

			tp->rx_opt.eff_sacks = 1;

			tp->selective_acks[0].start_seq = TCP_SKB_CB(skb)->seq;

			tp->selective_acks[0].end_seq =

						TCP_SKB_CB(skb)->end_seq;

net/ipv4/tcp_minisocks.c

+1 −2
Original line number Diff line number Diff line
@@ -434,9 +434,8 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req, 
		newtp->rx_opt.saw_tstamp = 0;



		newtp->rx_opt.dsack = 0;

		newtp->rx_opt.eff_sacks = 0;



		newtp->rx_opt.num_sacks = 0;



		newtp->urg_data = 0;



		if (sock_flag(newsk, SOCK_KEEPOPEN))

net/ipv4/tcp_output.c

+6 −6
Original line number Diff line number Diff line
@@ -441,10 +441,8 @@ static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp, 
			*ptr++ = htonl(sp[this_sack].end_seq);

		}



		if (tp->rx_opt.dsack) {

		if (tp->rx_opt.dsack)

			tp->rx_opt.dsack = 0;

			tp->rx_opt.eff_sacks = tp->rx_opt.num_sacks;

		}

	}

}
@@ -550,6 +548,7 @@ static unsigned tcp_established_options(struct sock *sk, struct sk_buff *skb, 
	struct tcp_skb_cb *tcb = skb ? TCP_SKB_CB(skb) : NULL;

	struct tcp_sock *tp = tcp_sk(sk);

	unsigned size = 0;

	unsigned int eff_sacks;



#ifdef CONFIG_TCP_MD5SIG

	*md5 = tp->af_specific->md5_lookup(sk, sk);
@@ -568,10 +567,11 @@ static unsigned tcp_established_options(struct sock *sk, struct sk_buff *skb, 
		size += TCPOLEN_TSTAMP_ALIGNED;

	}



	if (unlikely(tp->rx_opt.eff_sacks)) {

	eff_sacks = tp->rx_opt.num_sacks + tp->rx_opt.dsack;

	if (unlikely(eff_sacks)) {

		const unsigned remaining = MAX_TCP_OPTION_SPACE - size;

		opts->num_sack_blocks =

			min_t(unsigned, tp->rx_opt.eff_sacks,

			min_t(unsigned, eff_sacks,

			      (remaining - TCPOLEN_SACK_BASE_ALIGNED) /

			      TCPOLEN_SACK_PERBLOCK);

		size += TCPOLEN_SACK_BASE_ALIGNED +
@@ -1418,7 +1418,7 @@ static int tcp_mtu_probe(struct sock *sk) 
	    icsk->icsk_mtup.probe_size ||

	    inet_csk(sk)->icsk_ca_state != TCP_CA_Open ||

	    tp->snd_cwnd < 11 ||

	    tp->rx_opt.eff_sacks)

	    tp->rx_opt.num_sacks || tp->rx_opt.dsack)

		return -1;



	/* Very simple search strategy: just double the MSS. */