From ab5216a5bd453752f04bb79c29e8f01b11d69006 Mon Sep 17 00:00:00 2001 From: Vlad Yasevich Date: Thu, 19 Jun 2008 18:17:24 -0400 Subject: [PATCH] sctp: Optimize SFR-CACC transport list walking during SACK processing There is a possibility of walking the transport list twice during SACK processing when doing SFR-CACC algorithm. We can restructure the code to only do this once. Signed-off-by: Vlad Yasevich --- net/sctp/outqueue.c | 34 +++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 15 deletions(-) diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c index ef5ea7423cc8..c8de4da57f36 100644 --- a/net/sctp/outqueue.c +++ b/net/sctp/outqueue.c @@ -1145,27 +1145,31 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack) * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for * all destinations. - */ - if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { - primary->cacc.changeover_active = 0; - list_for_each_entry(transport, transport_list, - transports) { - transport->cacc.cycling_changeover = 0; - } - } - - /* - * SFR-CACC algorithm: * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE * is set the receiver of the SACK MUST take the following actions: * * A) Initialize the cacc_saw_newack to 0 for all destination * addresses. + * + * Only bother if changeover_active is set. Otherwise, this is + * totally suboptimal to do on every SACK. */ - if (gap_ack_blocks && - primary->cacc.changeover_active) { - list_for_each_entry(transport, transport_list, transports) { - transport->cacc.cacc_saw_newack = 0; + if (primary->cacc.changeover_active) { + u8 clear_cycling = 0; + + if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { + primary->cacc.changeover_active = 0; + clear_cycling = 1; + } + + if (clear_cycling || gap_ack_blocks) { + list_for_each_entry(transport, transport_list, + transports) { + if (clear_cycling) + transport->cacc.cycling_changeover = 0; + if (gap_ack_blocks) + transport->cacc.cacc_saw_newack = 0; + } } }