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Commit ab5216a5 authored by Vlad Yasevich's avatar Vlad Yasevich
Browse files

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: default avatarVlad Yasevich <vladislav.yasevich@hp.com>
parent 2cd9b822

net/sctp/outqueue.c

+19 −15
Original line number Diff line number Diff line
@@ -1145,29 +1145,33 @@ 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) {

	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;

			}

		}

	}



	/* Get the highest TSN in the sack. */

	highest_tsn = sack_ctsn;