On Fri, Jul 10, 2020 at 01:36:07PM +0200, Kurt Kanzenbach wrote: > +static void hellcreek_get_rxts(struct hellcreek *hellcreek, > + struct hellcreek_port_hwtstamp *ps, > + struct sk_buff *skb, struct sk_buff_head *rxq, > + int port) > +{ > + struct skb_shared_hwtstamps *shwt; > + struct sk_buff_head received; > + unsigned long flags; > + > + /* The latched timestamp belongs to one of the received frames. */ > + __skb_queue_head_init(&received); > + > + /* Lock & disable interrupts */ > + spin_lock_irqsave(&rxq->lock, flags); > + > + /* Add the reception queue "rxq" to the "received" queue an reintialize > + * "rxq". From now on, we deal with "received" not with "rxq" > + */ > + skb_queue_splice_tail_init(rxq, &received); > + > + spin_unlock_irqrestore(&rxq->lock, flags); > + > + for (; skb; skb = __skb_dequeue(&received)) { > + unsigned int type; > + u8 *hdr; > + u64 ns; > + > + /* Get nanoseconds from ptp packet */ > + type = SKB_PTP_TYPE(skb); > + hdr = parse_ptp_header(skb, type); > + ns = hellcreek_get_reserved_field(hdr); You might consider clearing the reserved field at this point. Some user space SW might consider non-zero reserved fields as corrupt! (The LinuxPTP stack doesn't do this, but still maybe others are more pedantic.) Acked-by: Richard Cochran <richardcochran@xxxxxxxxx>