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Harald Welte gerrit-no-reply at lists.osmocom.orgHarald Welte has submitted this change and it was merged.
Change subject: dyn TS: allow any pchan type changes, fix for gprs mode none
......................................................................
dyn TS: allow any pchan type changes, fix for gprs mode none
In rsl_chan_activate_lchan(), remove a condition to also allow switching pchan
modes when not in PDCH mode, which is actually not needed and would hinder
switching from pchan=NONE or between TCH/F <-> TCH/H.
Refactor the part where lchan_alloc() decides to switch a pchan mode into a
separate function, ts_usable_as_pchan(), which transparently checks both dyn TS
kinds for:
- Already in switchover? (missing check for ip.access style dyn TS)
- Is the lchan->state in error? (missing check for ip.access style dyn TS)
- Switch from pchan=NONE? (missing feature for Osmocom style dyn TS, for proper
handling with gprs mode none)
- Switch between TCH/F <-> TCH/H when all subslots are unused?
(missing feature for Osmocom style dyn TS, also useful for gprs mode none)
Always pass the desired pchan in the dyn_as_pchan argument to the _lc_find_*
functions to make switchover decisions transparent. Use the _lc_dyn_find_bts()
function for ip.access style dyn TS for the same reason.
Related: OS#3244
Change-Id: I72d5d833b186b1e1925d513885b405d8c19aa496
---
M src/libbsc/abis_rsl.c
M src/libbsc/chan_alloc.c
2 files changed, 96 insertions(+), 68 deletions(-)
Approvals:
Harald Welte: Looks good to me, approved
Jenkins Builder: Verified
diff --git a/src/libbsc/abis_rsl.c b/src/libbsc/abis_rsl.c
index e6d0cea..167ef6b 100644
--- a/src/libbsc/abis_rsl.c
+++ b/src/libbsc/abis_rsl.c
@@ -569,7 +569,6 @@
* released.
*/
if (lchan->ts->pchan == GSM_PCHAN_TCH_F_TCH_H_PDCH
- && lchan->ts->dyn.pchan_is == GSM_PCHAN_PDCH
&& lchan->ts->dyn.pchan_is == lchan->ts->dyn.pchan_want) {
enum gsm_phys_chan_config pchan_want;
pchan_want = pchan_for_lchant(lchan->type);
diff --git a/src/libbsc/chan_alloc.c b/src/libbsc/chan_alloc.c
index 9668968..bdb9d9d 100644
--- a/src/libbsc/chan_alloc.c
+++ b/src/libbsc/chan_alloc.c
@@ -133,9 +133,86 @@
return count;
}
+static bool ts_usable_as_pchan(struct gsm_bts_trx_ts *ts,
+ enum gsm_phys_chan_config as_pchan)
+{
+ switch (ts->pchan) {
+ case GSM_PCHAN_TCH_F_PDCH:
+ if (ts->flags & TS_F_PDCH_PENDING_MASK) {
+ /* currently being switched over. Not usable. */
+ return false;
+ }
+ switch (as_pchan) {
+ case GSM_PCHAN_TCH_F:
+ case GSM_PCHAN_PDCH:
+ /* continue to check below. */
+ break;
+ default:
+ return false;
+ }
+ break;
+
+ case GSM_PCHAN_TCH_F_TCH_H_PDCH:
+ if (ts->dyn.pchan_is != ts->dyn.pchan_want) {
+ /* currently being switched over. Not usable. */
+ return false;
+ }
+ switch (as_pchan) {
+ case GSM_PCHAN_TCH_F:
+ case GSM_PCHAN_TCH_H:
+ case GSM_PCHAN_PDCH:
+ /* continue to check below. */
+ break;
+ default:
+ return false;
+ }
+ break;
+
+ default:
+ /* static timeslots never switch. */
+ return ts->pchan == as_pchan;
+ }
+
+ /* Dynamic timeslots -- Checks depending on the current actual pchan mode: */
+ switch (ts_pchan(ts)) {
+ case GSM_PCHAN_NONE:
+ /* Not initialized, possibly because GPRS was disabled. We may switch. */
+ return true;
+
+ case GSM_PCHAN_PDCH:
+ /* This slot is in PDCH mode and available to switch pchan mode. But check for
+ * error states: */
+ if (ts->lchan->state != LCHAN_S_NONE && ts->lchan->state != LCHAN_S_ACTIVE)
+ return false;
+ return true;
+
+ case GSM_PCHAN_TCH_F:
+ case GSM_PCHAN_TCH_H:
+ /* No need to switch at all? */
+ if (ts_pchan(ts) == as_pchan)
+ return true;
+
+ /* If any lchan is in use, we can't change the pchan kind */
+ {
+ int ss;
+ int subslots = ts_subslots(ts);
+ for (ss = 0; ss < subslots; ss++) {
+ struct gsm_lchan *lc = &ts->lchan[ss];
+ if (lc->type != GSM_LCHAN_NONE || lc->state != LCHAN_S_NONE)
+ return false;
+ }
+ }
+ return true;
+
+ default:
+ /* Not implemented. */
+ return false;
+ }
+}
+
static struct gsm_lchan *
_lc_find_trx(struct gsm_bts_trx *trx, enum gsm_phys_chan_config pchan,
- enum gsm_phys_chan_config dyn_as_pchan)
+ enum gsm_phys_chan_config as_pchan)
{
struct gsm_bts_trx_ts *ts;
int j, start, stop, dir, ss;
@@ -160,72 +237,21 @@
ts = &trx->ts[j];
if (!ts_is_usable(ts))
continue;
+ /* The caller first selects what kind of TS to search in, e.g. looking for exact
+ * GSM_PCHAN_TCH_F, or maybe among dynamic GSM_PCHAN_TCH_F_TCH_H_PDCH... */
if (ts->pchan != pchan)
continue;
-
- /*
- * Allocation for fully dynamic timeslots
- * (does not apply for ip.access style GSM_PCHAN_TCH_F_PDCH)
- *
- * Note the special nature of a dynamic timeslot in PDCH mode:
- * in PDCH mode, typically, lchan->type is GSM_LCHAN_NONE and
- * lchan->state is LCHAN_S_NONE -- an otherwise unused slot
- * becomes PDCH implicitly. In the same sense, this channel
- * allocator will never be asked to find an available PDCH
- * slot; only TCH/F or TCH/H will be requested, and PDCH mode
- * means that it is available for switchover.
- *
- * A dynamic timeslot in PDCH mode may be switched to TCH/F or
- * TCH/H. If a dyn TS is already in TCH/F or TCH/H mode, it
- * means that it is in use and its mode can't be switched.
- *
- * The logic concerning channels for TCH/F is trivial: there is
- * only one channel, so a dynamic TS in TCH/F mode is already
- * taken and not available for allocation. For TCH/H, we need
- * to check whether a dynamic timeslot is already in TCH/H mode
- * and whether one of the two channels is still available.
- */
- switch (pchan) {
- case GSM_PCHAN_TCH_F_TCH_H_PDCH:
- if (ts->dyn.pchan_is != ts->dyn.pchan_want) {
- /* The TS's mode is being switched. Not
- * available anymore/yet. */
- DEBUGP(DRLL, "%s already in switchover\n",
- gsm_ts_and_pchan_name(ts));
- continue;
- }
- if (ts->dyn.pchan_is == GSM_PCHAN_PDCH) {
- /* This slot is available. Still check for
- * error states to be sure; in all cases the
- * first lchan will be used. */
- if (ts->lchan->state != LCHAN_S_NONE
- && ts->lchan->state != LCHAN_S_ACTIVE)
- continue;
- return ts->lchan;
- }
- if (ts->dyn.pchan_is != dyn_as_pchan)
- /* not applicable. */
- continue;
- /* The requested type matches the dynamic timeslot's
- * current mode. A channel may still be available
- * (think TCH/H). */
- check_subslots = ts_subslots(ts);
- break;
-
- case GSM_PCHAN_TCH_F_PDCH:
- /* Available for voice when in PDCH mode */
- if (ts_pchan(ts) != GSM_PCHAN_PDCH)
- continue;
- /* Subslots of a PDCH ts don't need to be checked. */
+ /* Next, is this timeslot in or can it be switched to the pchan we want to use it for? */
+ if (!ts_usable_as_pchan(ts, as_pchan))
+ continue;
+ /* If we need to switch it, after above check we are also allowed to switch it, and we
+ * will always use the first lchan after the switch. Return that lchan and rely on the
+ * caller to perform the pchan switchover. */
+ if (ts_pchan(ts) != as_pchan)
return ts->lchan;
- default:
- /* Not a dynamic channel, there is only one pchan kind: */
- check_subslots = ts_subslots(ts);
- break;
- }
-
- /* Is a sub-slot still available? */
+ /* TS is in desired pchan mode. Go ahead and check for an available lchan. */
+ check_subslots = ts_subslots(ts);
for (ss = 0; ss < check_subslots; ss++) {
struct gsm_lchan *lc = &ts->lchan[ss];
if (lc->type == GSM_LCHAN_NONE &&
@@ -264,7 +290,7 @@
static struct gsm_lchan *
_lc_find_bts(struct gsm_bts *bts, enum gsm_phys_chan_config pchan)
{
- return _lc_dyn_find_bts(bts, pchan, GSM_PCHAN_NONE);
+ return _lc_dyn_find_bts(bts, pchan, pchan);
}
/* Allocate a logical channel.
@@ -320,7 +346,8 @@
/* try dynamic TCH/F_PDCH */
if (lchan == NULL) {
- lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_F_PDCH);
+ lchan = _lc_dyn_find_bts(bts, GSM_PCHAN_TCH_F_PDCH,
+ GSM_PCHAN_TCH_F);
/* TCH/F_PDCH will be used as TCH/F */
if (lchan)
type = GSM_LCHAN_TCH_F;
@@ -349,7 +376,8 @@
}
/* If we don't have TCH/H either, try dynamic TCH/F_PDCH */
if (!lchan) {
- lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_F_PDCH);
+ lchan = _lc_dyn_find_bts(bts, GSM_PCHAN_TCH_F_PDCH,
+ GSM_PCHAN_TCH_F);
/* TCH/F_PDCH used as TCH/F -- here, type is already
* set to GSM_LCHAN_TCH_F, but for clarity's sake... */
if (lchan)
@@ -396,7 +424,8 @@
*/
/* If we don't have TCH/F either, try dynamic TCH/F_PDCH */
if (!lchan) {
- lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_F_PDCH);
+ lchan = _lc_dyn_find_bts(bts, GSM_PCHAN_TCH_F_PDCH,
+ GSM_PCHAN_TCH_F);
if (lchan)
type = GSM_LCHAN_TCH_F;
}
--
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Gerrit-MessageType: merged
Gerrit-Change-Id: I72d5d833b186b1e1925d513885b405d8c19aa496
Gerrit-PatchSet: 1
Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Owner: Neels Hofmeyr <nhofmeyr at sysmocom.de>
Gerrit-Reviewer: Harald Welte <laforge at gnumonks.org>
Gerrit-Reviewer: Jenkins Builder