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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
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+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)
+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