On Mon, Sep 26, 2016 at 05:47:51PM +0800, Xin Long wrote:
> Now sctp uses chunk->resent to record if a chunk is retransmitted, for
> RTT measurements with retransmitted DATA chunks. chunk->sent_count was
> introduced to record how many times one chunk has been sent for prsctp
> RTX policy before. We actually can know if one chunk is retransmitted
> by checking chunk->sent_count is greater than 1.
>
> This patch is to remove resent from sctp_chunk and reuse sent_count
> to avoid retransmitted chunks for RTT measurements.
>
> Signed-off-by: Xin Long <lucien....@gmail.com>
> ---
> include/net/sctp/structs.h | 1 -
> net/sctp/output.c | 3 ++-
> net/sctp/outqueue.c | 4 +---
> 3 files changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
> index 4f097f5..81a5faa 100644
> --- a/include/net/sctp/structs.h
> +++ b/include/net/sctp/structs.h
> @@ -647,7 +647,6 @@ struct sctp_chunk {
> #define SCTP_NEED_FRTX 0x1
> #define SCTP_DONT_FRTX 0x2
> __u16 rtt_in_progress:1, /* This chunk used for RTT calc? */
> - resent:1, /* Has this chunk ever been resent. */
> has_tsn:1, /* Does this chunk have a TSN yet? */
> has_ssn:1, /* Does this chunk have a SSN yet? */
> singleton:1, /* Only chunk in the packet? */
> diff --git a/net/sctp/output.c b/net/sctp/output.c
> index 31b7bc3..483d2ed 100644
> --- a/net/sctp/output.c
> +++ b/net/sctp/output.c
> @@ -547,7 +547,8 @@ int sctp_packet_transmit(struct sctp_packet *packet,
> gfp_t gfp)
> * for a given destination transport address.
> */
>
> - if (!chunk->resent && !tp->rto_pending) {
> + if (chunk->sent_count == 1 &&
> + !tp->rto_pending) {
> chunk->rtt_in_progress = 1;
> tp->rto_pending = 1;
> }
> diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
> index 72e54a4..2a629fa 100644
> --- a/net/sctp/outqueue.c
> +++ b/net/sctp/outqueue.c
> @@ -536,8 +536,6 @@ void sctp_retransmit_mark(struct sctp_outq *q,
> transport->rto_pending = 0;
> }
>
> - chunk->resent = 1;
> -
> /* Move the chunk to the retransmit queue. The chunks
> * on the retransmit queue are always kept in order.
> */
> @@ -1467,7 +1465,7 @@ static void sctp_check_transmitted(struct sctp_outq *q,
> * instance).
> */
> if (!tchunk->tsn_gap_acked &&
> - !tchunk->resent &&
> + tchunk->sent_count == 1 &&
> tchunk->rtt_in_progress) {
> tchunk->rtt_in_progress = 0;
> rtt = jiffies - tchunk->sent_at;
> --
> 2.1.0
>
Maybe wrap this in a macro? i.e.:
#define chunk_retransmitted(chunk) (chunk->sent_count > 1)
For readability?
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