fsm: factor out osmo_fsm_inst_term_children() from osmo_fsm_inst_term()

osmo_fsm_inst_term() has code for safe child removal, publish that part as
osmo_fsm_inst_term_children(); also use from osmo_fsm_inst_term().

As with osmo_fsm_inst_term(), add osmo_fsm_inst_term_children() macro to pass
the caller's source file and line to new _osmo_fsm_inst_term_children().

Rationale: in openbsc's VLR, I want to discard child FSMs when certain events
are handled. I could keep a pointer to each one, or simply iterate all
children, making the code a lot simpler in some places.

(Unfortunately, the patch may be displayed subobtimally. This really only moves
the children-loop to a new function, replaces it with a call to
_osmo_fsm_inst_term_children(fi, OSMO_FSM_TERM_PARENT, NULL, file, line) and
drops two local iterator variables. No other code changes are made, even though
the diff may show large removal + addition chunks)

Change-Id: I8dac1206259cbd251660f793ad023aaa1dc705a2
2 files changed