TCP_MTU_REDUCED_DEFERRED
TCPF_MTU_REDUCED_DEFERRED = BIT(TCP_MTU_REDUCED_DEFERRED),
if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,