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osmo-bts-trx: fix hopping pointer bug in trx_sched_fn() 

In change [1] together with the actual implementation I introduced
a serious bug to trx_sched_fn(): if a timeslot is configured to use
frequency hopping, both 'pinst' and 'l1h' pointers are *overwriten*
in the inner loop, so the Downlink burst is re-directed to the
approproate PHY instance.  However, if a subsequent timeslot is not
hopping, the Downlink burst would be re-directed to the wrong PHY
instance because both pointers were overwriten during a previous
iteration.

Let's add another 'struct phy_instance' pointer to the inner loop,
so it's properly re-initialized for each timeslot iteration.

Change-Id: I9afbbef8dc5d885763356470c27d4392dce8e815
Fixes: [1] I68f4ae09fd0789ad0d8f1c1e17e17dfc4de8e462
Related: SYS#4868, OS#4546
This commit is contained in:
Vadim Yanitskiy 2021-05-17 02:28:28 +02:00
parent f4c2b61e3e
commit 1c2c92da17
1 changed files with 6 additions and 5 deletions
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11
src/osmo-bts-trx/scheduler_trx.c
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@ -107,9 +107,9 @@ static void trx_sched_fn(struct gsm_bts *bts, const uint32_t fn)
/* process every TRX */
llist_for_each_entry(trx, &bts->trx_list, list) {
struct phy_instance *pinst = trx_phy_instance(trx);
struct phy_link *plink = pinst->phy_link;
struct trx_l1h *l1h = pinst->u.osmotrx.hdl;
const struct phy_instance *_pinst = trx_phy_instance(trx);
const struct phy_link *plink = _pinst->phy_link;
struct trx_l1h *l1h = _pinst->u.osmotrx.hdl;
struct l1sched_trx *l1t = &l1h->l1s;
/* we don't schedule, if power is off */
@ -122,6 +122,8 @@ static void trx_sched_fn(struct gsm_bts *bts, const uint32_t fn)
/* process every TS of TRX */
for (tn = 0; tn < ARRAY_SIZE(l1t->ts); tn++) {
const struct phy_instance *pinst = _pinst;
/* ready-to-send */
_sched_rts(l1t, tn, GSM_TDMA_FN_SUM(sched_fn, plink->u.osmotrx.rts_advance));
@ -143,7 +145,6 @@ static void trx_sched_fn(struct gsm_bts *bts, const uint32_t fn)
pinst = dlfh_route_br(&br, &trx->ts[tn]);
if (pinst == NULL)
continue;
l1h = pinst->u.osmotrx.hdl;
}
if (pinst->trx == bts->c0) {
@ -153,7 +154,7 @@ static void trx_sched_fn(struct gsm_bts *bts, const uint32_t fn)
br.att = 0;
}
trx_if_send_burst(l1h, &br);
trx_if_send_burst(pinst->u.osmotrx.hdl, &br);
}
}