Re: [PATCH net-next 3/7] idpf: support pacing offload

On 7/6/2026 6:34 AM, Willem de Bruijn wrote:

...

+static void idpf_tx_splitq_set_txtime(const struct idpf_tx_queue *tx_q,
+				      const struct sk_buff *skb,
+				      struct idpf_tx_splitq_params *tx_params)
+{
+	const int ts_gran_pow2 = 9;
+	u64 ts, now;
+
+	/* Skip if netpoll: not needed and not safe to call ktime helpers */
+	if (netpoll_tx_running(skb->dev))
+		return;
+
+	switch (skb->tstamp_type) {
+	case SKB_CLOCK_REALTIME:
+		ts = ktime_to_ns(ktime_add(skb->tstamp,
+					   ktime_mono_to_any(0, TK_OFFS_TAI) -
+					   ktime_mono_to_any(0, TK_OFFS_REAL)));
+		break;
+	case SKB_CLOCK_MONOTONIC:
+		ts = ktime_to_ns(ktime_mono_to_any(skb->tstamp, TK_OFFS_TAI));
+		break;
+	case SKB_CLOCK_TAI:
+		ts = ktime_to_ns(skb->tstamp);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		return;
+	}
+
+	now = ktime_get_clocktai_ns();
+	if (ts < now)
+		return;
+
+	/* beyond offload horizon? set overflow bit only */
+	if (ts > now + ((u64)skb->dev->pacing_offload_horizon * NSEC_PER_USEC)) {
+		tx_params->offload.desc_ts[2] = 1 << 7;
+		return;
+	}
+
+	ts >>= ts_gran_pow2;
+
+	tx_params->offload.desc_ts[0] = ts & 0xff;
+	tx_params->offload.desc_ts[1] = (ts >> 8) & 0xff;
+	tx_params->offload.desc_ts[2] = ((ts >> 16) & 0x7f);
+
+	/* 0 is valid 24b timestamp, but also means field unset.
+	 * Add 512 ns (ts_gran_pow2) to avoid this case
+	 */
+	if ((ts & 0x7fffff) == 0)
+		tx_params->offload.desc_ts[0] = 1;
+}

Slight nit but seems like this check can be moved before the assignments 
(and then return) as we don't need to assign the other 2 bytes in this 
situation?

Thanks,
Tony