sfc: Rate-limit log message for PTP packets without a matching timestamp event

In case of a flood of PTP packets, the timestamp peripheral and MC
firmware on the SFN[56]322F boards may not be able to provide
timestamp events for all packets.  Don't complain too much about this.

Fixes: 7c236c43b838 ('sfc: Add support for IEEE-1588 PTP')
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c
index 8b2cf783217c..8c665f1b5480 100644
--- a/drivers/net/ethernet/sfc/ptp.c
+++ b/drivers/net/ethernet/sfc/ptp.c
@@ -717,8 +717,9 @@ static bool efx_ptp_process_events(struct efx_nic *efx, struct sk_buff_head *q)
                         __skb_queue_tail(q, skb);
                 } else if (time_after(jiffies, match->expiry)) {
                         match->state = PTP_PACKET_STATE_TIMED_OUT;
-                        netif_warn(efx, rx_err, efx->net_dev,
-                                   "PTP packet - no timestamp seen\n");
+                        if (net_ratelimit())
+                                netif_warn(efx, rx_err, efx->net_dev,
+                                           "PTP packet - no timestamp seen\n");
                         __skb_queue_tail(q, skb);
                 } else {
                         /* Replace unprocessed entry and stop */