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Commit b7e445a1 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'tcp-RACK-loss-recovery-bug-fixes' 



Yuchung Cheng says:

====================
tcp: RACK loss recovery bug fixes

This patch set has four minor bug fixes in TCP RACK loss recovery.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 2edbdb31 6065fd0d

net/ipv4/tcp_input.c

+1 −0
Original line number Diff line number Diff line
@@ -2329,6 +2329,7 @@ static void tcp_undo_cwnd_reduction(struct sock *sk, bool unmark_loss) 
	}

	tp->snd_cwnd_stamp = tcp_jiffies32;

	tp->undo_marker = 0;

	tp->rack.advanced = 1; /* Force RACK to re-exam losses */

}



static inline bool tcp_may_undo(const struct tcp_sock *tp)

net/ipv4/tcp_recovery.c

+13 −15
Original line number Diff line number Diff line
@@ -55,7 +55,8 @@ static void tcp_rack_detect_loss(struct sock *sk, u32 *reo_timeout) 
	 * to queuing or delayed ACKs.

	 */

	reo_wnd = 1000;

	if ((tp->rack.reord || !tp->lost_out) && min_rtt != ~0U) {

	if ((tp->rack.reord || inet_csk(sk)->icsk_ca_state < TCP_CA_Recovery) &&

	    min_rtt != ~0U) {

		reo_wnd = max((min_rtt >> 2) * tp->rack.reo_wnd_steps, reo_wnd);

		reo_wnd = min(reo_wnd, tp->srtt_us >> 3);

	}
@@ -79,12 +80,12 @@ static void tcp_rack_detect_loss(struct sock *sk, u32 *reo_timeout) 
		 */

		remaining = tp->rack.rtt_us + reo_wnd -

			    tcp_stamp_us_delta(tp->tcp_mstamp, skb->skb_mstamp);

		if (remaining < 0) {

		if (remaining <= 0) {

			tcp_rack_mark_skb_lost(sk, skb);

			list_del_init(&skb->tcp_tsorted_anchor);

		} else {

			/* Record maximum wait time (+1 to avoid 0) */

			*reo_timeout = max_t(u32, *reo_timeout, 1 + remaining);

			/* Record maximum wait time */

			*reo_timeout = max_t(u32, *reo_timeout, remaining);

		}

	}

}
@@ -116,13 +117,8 @@ void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, 
{

	u32 rtt_us;



	if (tp->rack.mstamp &&

	    !tcp_rack_sent_after(xmit_time, tp->rack.mstamp,

				 end_seq, tp->rack.end_seq))

		return;



	rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, xmit_time);

	if (sacked & TCPCB_RETRANS) {

	if (rtt_us < tcp_min_rtt(tp) && (sacked & TCPCB_RETRANS)) {

		/* If the sacked packet was retransmitted, it's ambiguous

		 * whether the retransmission or the original (or the prior

		 * retransmission) was sacked.
@@ -133,13 +129,15 @@ void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, 
		 * so it's at least one RTT (i.e., retransmission is at least

		 * an RTT later).

		 */

		if (rtt_us < tcp_min_rtt(tp))

		return;

	}

	tp->rack.advanced = 1;

	tp->rack.rtt_us = rtt_us;

	if (tcp_rack_sent_after(xmit_time, tp->rack.mstamp,

				end_seq, tp->rack.end_seq)) {

		tp->rack.mstamp = xmit_time;

		tp->rack.end_seq = end_seq;

	tp->rack.advanced = 1;

	}

}



/* We have waited long enough to accommodate reordering. Mark the expired