ct_rcu_watching_cpu
snap = ct_rcu_watching_cpu(cpu) & ~CT_RCU_WATCHING;
return snap == ct_rcu_watching_cpu(cpu);
WARN_ON_ONCE(rcu_watching_snap_in_eqs(ct_rcu_watching_cpu(cpu)));
rcu_watching_snap_in_eqs(ct_rcu_watching_cpu(cpu));
ct_rcu_watching_cpu(cpu) & 0xffff,