OK. Please explain. Looking at tstate assignment

In posixmodule.c:PyOSAfterFork_Child()
    PyStatus status;
    _PyRuntimeState *runtime = &_PyRuntime;

...
    PyThreadState *tstate = _PyThreadState_GET();

and later calls
    status = _PyRuntimeState_ReInitThreads(runtime);

Yet in Posix/ceval.c
PyStatus
_PyEval_ReInitThreads(PyThreadState *tstate)
{
    _PyRuntimeState *runtime = tstate->interp->runtime;

** this looks like runtime->interp->runtime

And then we get down to:
    /* Destroy all threads except the current one */
    _PyThreadState_DeleteExcept(runtime, tstate);

Is this correct - as it looks like:
_PyThreadState_DeleteExcept(runtime->interp->runtime, runtime) -- where runtime == &_PyRuntime;