pespin has submitted this change. ( https://gerrit.osmocom.org/c/osmo-pcu/+/33454 )

Change subject: Avoid re-assigning DL TBF over PACCH upon duplicate FinalACKs received ......................................................................

Avoid re-assigning DL TBF over PACCH upon duplicate FinalACKs received

Due to the fn-advance feature, we schedule DL blocks in advance, which may make several retransmitted DL ACK/NACK [RRBP] be in flight, and hence several of them may be answered by the MS. When the first one is received, we attempt to initiate a PktDlAss over PACCH if new DL data was received meanwhile from SGSN. However, if we receive duplicates of that final PKT CTRL ACK, we don't want to re-initiate it again, since it is already ongoing.

Related: OS#5471 Change-Id: Idc204aba61ad98f75853dcd46200f5dcc4139203 --- M src/tbf_dl.cpp M src/tbf_dl_fsm.c 2 files changed, 29 insertions(+), 8 deletions(-)

Approvals: fixeria: Looks good to me, but someone else must approve laforge: Looks good to me, but someone else must approve Jenkins Builder: Verified pespin: Looks good to me, approved

diff --git a/src/tbf_dl.cpp b/src/tbf_dl.cpp index 40442c3..f4439d3 100644 --- a/src/tbf_dl.cpp +++ b/src/tbf_dl.cpp @@ -1053,9 +1053,7 @@ int gprs_rlcmac_dl_tbf::rcvd_dl_final_ack() { uint16_t received; - int rc = 0; - - osmo_fsm_inst_dispatch(this->state_fi, TBF_EV_FINAL_ACK_RECVD, NULL); + int rc;

/* range V(A)..V(S)-1 */ received = m_window.count_unacked(); @@ -1064,10 +1062,7 @@ m_tx_counter = 0; m_window.reset();

- /* check for LLC PDU in the LLC Queue */ - if (llc_queue_size(llc_queue()) > 0) - /* we have more data so we will re-use this tbf */ - rc = ms_new_dl_tbf_assigned_on_pacch(ms(), dl_tbf_as_tbf(this)); + rc = osmo_fsm_inst_dispatch(this->state_fi, TBF_EV_FINAL_ACK_RECVD, NULL);

return rc; } diff --git a/src/tbf_dl_fsm.c b/src/tbf_dl_fsm.c index ba7fc5a..557fb7a 100644 --- a/src/tbf_dl_fsm.c +++ b/src/tbf_dl_fsm.c @@ -260,8 +260,10 @@ static void st_wait_release_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state) { struct tbf_dl_fsm_ctx *ctx = (struct tbf_dl_fsm_ctx *)fi->priv; + struct GprsMs *ms = tbf_ms(ctx->tbf);

- /* T3192 is running on the MS and has also been armed by this FSM now. + /* This state was entered because FinalACK was received; now T3192 is + * running on the MS and has also been armed by this FSM. * During that time, it is possible to reach the MS over PACCH to assign * new DL TBF. * Upon T3192 expiration, FSM will transition to TBF_ST_WAIT_REUSE_TFI @@ -270,6 +272,12 @@ */

mod_ass_type(ctx, GPRS_RLCMAC_FLAG_CCCH, false); + + /* check for LLC PDU in the LLC Queue */ + if (llc_queue_size(ms_llc_queue(ms)) > 0) { + /* we have more data so we will re-use this tbf */ + ms_new_dl_tbf_assigned_on_pacch(ms, ctx->tbf); + } }

static void st_wait_release(struct osmo_fsm_inst *fi, uint32_t event, void *data)