if (time_after_eq(now, t)) {
trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);
cmpxchg(&call->delay_ack_at, t, now + MAX_JIFFY_OFFSET);
if (time_after_eq(now, t)) {
trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);
cmpxchg(&call->delay_ack_at, t, now + MAX_JIFFY_OFFSET);