lchan_select: prepare a list of timeslots once, iterate over it

The lchan_avail_by_type() attempts to find an unused lchan for the
given GSM_LCHAN_* value: TCH/F, TCH/H, or SDCCH.  This is achieved
by looking up timeslots with compatible GSM_PCHAN_* values.

For instance, finding an unused SDCCH lchan may involve:

* attempt to find a timeslot with pchan=GSM_PCHAN_CCCH_SDCCH4,
* attempt to find a timeslot with pchan=GSM_PCHAN_CCCH_SDCCH4_CBCH,
* attempt to find a timeslot with pchan=GSM_PCHAN_SDCCH8_SACCH8C,
* attempt to find a timeslot with pchan=GSM_PCHAN_SDCCH8_SACCH8C_CBCH,
* attempt to find a timeslot with pchan=GSM_PCHAN_OSMO_DYN (switched),
* attempt to find a timeslot with pchan=GSM_PCHAN_OSMO_DYN (not switched).

Each attempt involves iterating over all timeslots of each TRX,
either in ascending or in descending order (see _lc_dyn_find_bts()
and _lc_find_trx()).

This patch simplifies the lookup logic by preparing a monolithic
array of timeslot pointers once, and then using that array for
each GSM_PCHAN_* lookup attempt.  This also facilitates adding
more complex (than ascending/descending) allocation algorithms.

Change-Id: I7ccc56856bfd40fd7c63b7437736de60c2b516ff
Related: SYS#5460

0 files changed, 0 insertions, 0 deletions