net: sctp: Open out the check for Nagle
The check for Nagle contains 6 separate checks all of which must be true before a data packet is delayed. Separate out each into its own 'if (test) return SCTP_XMIT_OK' so that the reasons can be individually described. Also return directly with SCTP_XMIT_RWND_FULL. Delete the now-unused 'retval' variable and 'finish' label from sctp_packet_can_append_data(). Signed-off-by: David Laight <david.laight@aculab.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -633,7 +633,6 @@ nomem:
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static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet,
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struct sctp_chunk *chunk)
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{
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sctp_xmit_t retval = SCTP_XMIT_OK;
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size_t datasize, rwnd, inflight, flight_size;
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struct sctp_transport *transport = packet->transport;
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struct sctp_association *asoc = transport->asoc;
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@ -658,15 +657,11 @@ static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet,
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datasize = sctp_data_size(chunk);
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if (datasize > rwnd) {
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if (inflight > 0) {
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/* We have (at least) one data chunk in flight,
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* so we can't fall back to rule 6.1 B).
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*/
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retval = SCTP_XMIT_RWND_FULL;
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goto finish;
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}
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}
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if (datasize > rwnd && inflight > 0)
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/* We have (at least) one data chunk in flight,
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* so we can't fall back to rule 6.1 B).
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*/
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return SCTP_XMIT_RWND_FULL;
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/* RFC 2960 6.1 Transmission of DATA Chunks
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*
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@ -680,36 +675,44 @@ static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet,
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* When a Fast Retransmit is being performed the sender SHOULD
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* ignore the value of cwnd and SHOULD NOT delay retransmission.
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*/
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if (chunk->fast_retransmit != SCTP_NEED_FRTX)
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if (flight_size >= transport->cwnd) {
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retval = SCTP_XMIT_RWND_FULL;
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goto finish;
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}
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if (chunk->fast_retransmit != SCTP_NEED_FRTX &&
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flight_size >= transport->cwnd)
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return SCTP_XMIT_RWND_FULL;
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/* Nagle's algorithm to solve small-packet problem:
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* Inhibit the sending of new chunks when new outgoing data arrives
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* if any previously transmitted data on the connection remains
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* unacknowledged.
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*/
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if (!sctp_sk(asoc->base.sk)->nodelay && sctp_packet_empty(packet) &&
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inflight && sctp_state(asoc, ESTABLISHED)) {
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unsigned int max = transport->pathmtu - packet->overhead;
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unsigned int len = chunk->skb->len + q->out_qlen;
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/* Check whether this chunk and all the rest of pending
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* data will fit or delay in hopes of bundling a full
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* sized packet.
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* Don't delay large message writes that may have been
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* fragmeneted into small peices.
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*/
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if ((len < max) && chunk->msg->can_delay) {
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retval = SCTP_XMIT_NAGLE_DELAY;
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goto finish;
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}
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}
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if (sctp_sk(asoc->base.sk)->nodelay)
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/* Nagle disabled */
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return SCTP_XMIT_OK;
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finish:
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return retval;
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if (!sctp_packet_empty(packet))
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/* Append to packet */
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return SCTP_XMIT_OK;
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if (inflight == 0)
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/* Nothing unacked */
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return SCTP_XMIT_OK;
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if (!sctp_state(asoc, ESTABLISHED))
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return SCTP_XMIT_OK;
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/* Check whether this chunk and all the rest of pending data will fit
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* or delay in hopes of bundling a full sized packet.
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*/
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if (chunk->skb->len + q->out_qlen >= transport->pathmtu - packet->overhead)
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/* Enough data queued to fill a packet */
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return SCTP_XMIT_OK;
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/* Don't delay large message writes that may have been fragmented */
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if (!chunk->msg->can_delay)
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return SCTP_XMIT_OK;
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/* Defer until all data acked or packet full */
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return SCTP_XMIT_NAGLE_DELAY;
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}
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/* This private function does management things when adding DATA chunk */
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