CLOSURE_RUNNING
((CLOSURE_DESTRUCTOR|CLOSURE_WAITING|CLOSURE_RUNNING) << 1)
#define CLOSURE_REMAINING_INITIALIZER (1|CLOSURE_RUNNING)
atomic_sub(CLOSURE_RUNNING, &cl->remaining);
closure_sub(_cl, CLOSURE_RUNNING + 1); \
closure_sub(_cl, CLOSURE_RUNNING - CLOSURE_DESTRUCTOR + 1); \
unsigned flags = atomic_sub_return_release(1 + CLOSURE_RUNNING - CLOSURE_DESTRUCTOR,
if (!old || (old & CLOSURE_RUNNING))
r & CLOSURE_RUNNING ? "R" : "");