static void tcp_undo_cwnd_reduction(struct sock *sk, bool unmark_loss)
{
	struct tcp_sock *tp = tcp_sk(sk);

	if (unmark_loss) {
		struct sk_buff *skb;

		tcp_for_write_queue(skb, sk) {
			if (skb == tcp_send_head(sk))
				break;
			TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
		}
		tp->lost_out = 0;
		tcp_clear_all_retrans_hints(tp);
	}

	if (tp->prior_ssthresh) {
		const struct inet_connection_sock *icsk = inet_csk(sk);

		if (icsk->icsk_ca_ops->undo_cwnd)
			tp->snd_cwnd = icsk->icsk_ca_ops->undo_cwnd(sk);
		else
			tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh << 1);

		if (tp->prior_ssthresh > tp->snd_ssthresh) {
			tp->snd_ssthresh = tp->prior_ssthresh;
			tcp_ecn_withdraw_cwr(tp);
		}
	}
	tp->snd_cwnd_stamp = tcp_time_stamp;
	tp->undo_marker = 0;
}
Unknown