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From: "Ilpo Järvinen" <ilpo.jarvinen@helsinki.fi>
To: netdev@vger.kernel.org
Cc: Yuchung Cheng <ycheng@google.com>,
	Neal Cardwell <ncardwell@google.com>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Olivier Tilmans <olivier.tilmans@nokia-bell-labs.com>
Subject: [RFC PATCH 18/28] tcp: don't early return when sack doesn't fit
Date: Wed, 18 Mar 2020 11:37:59 +0200	[thread overview]
Message-ID: <1584524289-24187-18-git-send-email-ilpo.jarvinen@helsinki.fi> (raw)
In-Reply-To: <1584524289-24187-2-git-send-email-ilpo.jarvinen@helsinki.fi>

From: Ilpo Järvinen <ilpo.jarvinen@cs.helsinki.fi>

AccECN code will be placed after this fragment so no early
returns please.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@cs.helsinki.fi>
---
 net/ipv4/tcp_output.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 9ff6d14363df..084ebd2e725f 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -875,17 +875,16 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
 	eff_sacks = tp->rx_opt.num_sacks + tp->rx_opt.dsack;
 	if (unlikely(eff_sacks)) {
 		const unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
-		if (unlikely(remaining < TCPOLEN_SACK_BASE_ALIGNED +
-					 TCPOLEN_SACK_PERBLOCK))
-			return size;
-
-		opts->num_sack_blocks =
-			min_t(unsigned int, eff_sacks,
-			      (remaining - TCPOLEN_SACK_BASE_ALIGNED) /
-			      TCPOLEN_SACK_PERBLOCK);
-
-		size += TCPOLEN_SACK_BASE_ALIGNED +
-			opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
+		if (likely(remaining >= TCPOLEN_SACK_BASE_ALIGNED +
+					 TCPOLEN_SACK_PERBLOCK)) {
+			opts->num_sack_blocks =
+				min_t(unsigned int, eff_sacks,
+				      (remaining - TCPOLEN_SACK_BASE_ALIGNED) /
+				      TCPOLEN_SACK_PERBLOCK);
+
+			size += TCPOLEN_SACK_BASE_ALIGNED +
+				opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
+		}
 	}
 
 	return size;
-- 
2.20.1


  parent reply	other threads:[~2020-03-18  9:46 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-18  9:37 [RFC PATCH 02/28] tcp: fast path functions later Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 03/28] tcp: move tcp_in_ack_event later Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 04/28] tcp: create FLAG_TS_PROGRESS Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 05/28] tcp: extend TCP flags to allow AE bit/ACE field Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 06/28] tcp: reorganize SYN ECN code Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 07/28] tcp: rework {__,}tcp_ecn_check_ce() -> tcp_data_ecn_check() Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 08/28] tcp: helpers for ECN mode handling Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 09/28] gso: AccECN support Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 10/28] gro: prevent ACE field corruption & better AccECN handling Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 11/28] tcp: AccECN support to tcp_add_backlog Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 12/28] tcp: AccECN core Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 13/28] tcp: Pass flags to tcp_send_ack Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 14/28] tcp: AccECN negotiation Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 15/28] tcp: add AccECN rx byte counters Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 16/28] tcp: allow embedding leftover into option padding Ilpo Järvinen
2020-03-18  9:37 ` [RFC PATCH 17/28] tcp: AccECN needs to know delivered bytes Ilpo Järvinen
2020-03-18  9:37 ` Ilpo Järvinen [this message]
2020-03-18  9:38 ` [RFC PATCH 19/28] tcp: AccECN option Ilpo Järvinen
2020-03-18  9:38 ` [RFC PATCH 20/28] tcp: AccECN option send control Ilpo Järvinen
2020-03-18  9:38 ` [RFC PATCH 21/28] tcp: AccECN option beacon Ilpo Järvinen
2020-03-18  9:38 ` [RFC PATCH 22/28] tcp: AccECN option order bit & failure handling Ilpo Järvinen
2020-03-18  9:38 ` [RFC PATCH 23/28] tcp: AccECN option ceb/cep heuristic Ilpo Järvinen
2020-03-18  9:38 ` [RFC PATCH 24/28] tcp: try to fit AccECN option with SACK Ilpo Järvinen
2020-03-18  9:38 ` [RFC PATCH 25/28] tcp: try to avoid safer when ACKs are thinned Ilpo Järvinen
2020-03-18  9:38 ` [RFC PATCH 26/28] tcp: to prevent runaway AccECN cep/ACE deficit, limit GSO size Ilpo Järvinen
2020-03-18  9:38 ` [RFC PATCH 27/28] gro: flushing when CWR is set negatively affects AccECN Ilpo Järvinen
2020-03-18  9:38 ` [RFC PATCH 28/28] tcp: AccECN sysctl documentation Ilpo Järvinen
2020-03-18  9:43 [RFC PATCH 00/28]: Accurate ECN for TCP Ilpo Järvinen
2020-03-18  9:43 ` [RFC PATCH 18/28] tcp: don't early return when sack doesn't fit Ilpo Järvinen

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