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[DCCP]: Simplify interface of dccp_sample_rtt

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The third parameter of dccp_sample_rtt now becomes useless and is removed.

Also combined the subtraction of the timestamp echo and the elapsed time.
This is safe, since (a) presence of timestamp echo is tested first and (b)
elapsed time is either present and non-zero or it is not set and equals 0
due to the memset in dccp_parse_options.

To avoid measuring option-processing time, the timestamp for measuring the
initial Request/Response RTT sample is taken directly when the function is
called (the Linux implementation always adds a timestamp on the Request,
so there is no loss in doing this).

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Gerrit Renker
2007-09-25 22:40:44 -07:00
committed by David S. Miller
parent 4c70f383e0
commit 3393da8241
3 changed files with 19 additions and 34 deletions
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6
net/dccp/ccids/ccid3.c
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@@ -448,7 +448,7 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
* Calculate new round trip sample as per [RFC 3448, 4.3] by
* R_sample = (now - t_recvdata) - t_elapsed
*/
r_sample = dccp_sample_rtt(sk, now, &packet->dccphtx_tstamp);
r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, packet->dccphtx_tstamp));
/*
* Update RTT estimate by
@@ -881,9 +881,9 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
case DCCP_PKT_DATAACK:
if (opt_recv->dccpor_timestamp_echo == 0)
break;
r_sample = dccp_timestamp() - opt_recv->dccpor_timestamp_echo;
rtt_prev = hcrx->ccid3hcrx_rtt;
now = ktime_get_real();
r_sample = dccp_sample_rtt(sk, now, NULL);
r_sample = dccp_sample_rtt(sk, 10 * r_sample);
if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
hcrx->ccid3hcrx_rtt = r_sample;