prison_find_child
pr = prison_find_child(curthread->td_ucred->cr_prison, id);
pr = prison_find_child(curthread->td_ucred->cr_prison,
pr = prison_find_child(mypr, jid);
pr = prison_find_child(td->td_ucred->cr_prison, uap->jid);
pr = prison_find_child(td->td_ucred->cr_prison, uap->jid);
pr = prison_find_child(td->td_ucred->cr_prison, jid);
pr = prison_find_child(td->td_ucred->cr_prison, jid);
struct prison *prison_find_child(struct prison *, int);