Commit cadbd031 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

[TCP]: Dropped unnecessary skb/sacked accessing in reneging 



SACK reneging can be precalculated to a FLAG in clean_rtx_queue
which has the right skb looked up. This will help a bit in
future because skb->sacked access will be changed eventually,
changing it already won't hurt any.

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 90840def

net/ipv4/tcp_input.c

+13 −12
Original line number Diff line number Diff line
@@ -105,6 +105,7 @@ int sysctl_tcp_abc __read_mostly; 
#define FLAG_SND_UNA_ADVANCED	0x400 /* Snd_una was changed (!= FLAG_DATA_ACKED) */

#define FLAG_DSACKING_ACK	0x800 /* SACK blocks contained D-SACK info */

#define FLAG_NONHEAD_RETRANS_ACKED	0x1000 /* Non-head rexmitted data was ACKed */

#define FLAG_SACK_RENEGING	0x2000 /* snd_una advanced to a sacked seq */



#define FLAG_ACKED		(FLAG_DATA_ACKED|FLAG_SYN_ACKED)

#define FLAG_NOT_DUP		(FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED)
@@ -1918,18 +1919,15 @@ void tcp_enter_loss(struct sock *sk, int how) 
	tp->frto_counter = 0;

}



static int tcp_check_sack_reneging(struct sock *sk)

{

	struct sk_buff *skb;



	/* If ACK arrived pointing to a remembered SACK,

	 * it means that our remembered SACKs do not reflect

	 * real state of receiver i.e.

/* If ACK arrived pointing to a remembered SACK, it means that our

 * remembered SACKs do not reflect real state of receiver i.e.

 * receiver _host_ is heavily congested (or buggy).

 *

 * Do processing similar to RTO timeout.

 */

	if ((skb = tcp_write_queue_head(sk)) != NULL &&

	    (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) {

static int tcp_check_sack_reneging(struct sock *sk, int flag)

{

	if (flag & FLAG_SACK_RENEGING) {

		struct inet_connection_sock *icsk = inet_csk(sk);

		NET_INC_STATS_BH(LINUX_MIB_TCPSACKRENEGING);
@@ -2515,7 +2513,7 @@ tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag) 
		tp->prior_ssthresh = 0;



	/* B. In all the states check for reneging SACKs. */

	if (tp->sacked_out && tcp_check_sack_reneging(sk))

	if (tcp_check_sack_reneging(sk, flag))

		return;



	/* C. Process data loss notification, provided it is valid. */
@@ -2852,6 +2850,9 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets) 
		tcp_clear_all_retrans_hints(tp);

	}



	if (skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))

		flag |= FLAG_SACK_RENEGING;



	if (flag & FLAG_ACKED) {

		const struct tcp_congestion_ops *ca_ops

			= inet_csk(sk)->icsk_ca_ops;

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