sfc: PTP: Moderate log message on event queue overflow
Limit syslog flood if a PTP packet storm occurs.
Fixes: 7c236c43b838 ('sfc: Add support for IEEE-1588 PTP')
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c
index 93a61a1..8b2cf78 100644
--- a/drivers/net/ethernet/sfc/ptp.c
+++ b/drivers/net/ethernet/sfc/ptp.c
@@ -220,6 +220,7 @@
* @evt_list: List of MC receive events awaiting packets
* @evt_free_list: List of free events
* @evt_lock: Lock for manipulating evt_list and evt_free_list
+ * @evt_overflow: Boolean indicating that event list has overflowed
* @rx_evts: Instantiated events (on evt_list and evt_free_list)
* @workwq: Work queue for processing pending PTP operations
* @work: Work task
@@ -270,6 +271,7 @@
struct list_head evt_list;
struct list_head evt_free_list;
spinlock_t evt_lock;
+ bool evt_overflow;
struct efx_ptp_event_rx rx_evts[MAX_RECEIVE_EVENTS];
struct workqueue_struct *workwq;
struct work_struct work;
@@ -635,6 +637,11 @@
}
}
}
+ /* If the event overflow flag is set and the event list is now empty
+ * clear the flag to re-enable the overflow warning message.
+ */
+ if (ptp->evt_overflow && list_empty(&ptp->evt_list))
+ ptp->evt_overflow = false;
spin_unlock_bh(&ptp->evt_lock);
}
@@ -676,6 +683,11 @@
break;
}
}
+ /* If the event overflow flag is set and the event list is now empty
+ * clear the flag to re-enable the overflow warning message.
+ */
+ if (ptp->evt_overflow && list_empty(&ptp->evt_list))
+ ptp->evt_overflow = false;
spin_unlock_bh(&ptp->evt_lock);
return rc;
@@ -809,6 +821,7 @@
list_for_each_safe(cursor, next, &efx->ptp_data->evt_list) {
list_move(cursor, &efx->ptp_data->evt_free_list);
}
+ ptp->evt_overflow = false;
spin_unlock_bh(&efx->ptp_data->evt_lock);
return rc;
@@ -901,6 +914,7 @@
spin_lock_init(&ptp->evt_lock);
for (pos = 0; pos < MAX_RECEIVE_EVENTS; pos++)
list_add(&ptp->rx_evts[pos].link, &ptp->evt_free_list);
+ ptp->evt_overflow = false;
ptp->phc_clock_info.owner = THIS_MODULE;
snprintf(ptp->phc_clock_info.name,
@@ -1299,8 +1313,13 @@
list_add_tail(&evt->link, &ptp->evt_list);
queue_work(ptp->workwq, &ptp->work);
- } else {
- netif_err(efx, rx_err, efx->net_dev, "No free PTP event");
+ } else if (!ptp->evt_overflow) {
+ /* Log a warning message and set the event overflow flag.
+ * The message won't be logged again until the event queue
+ * becomes empty.
+ */
+ netif_err(efx, rx_err, efx->net_dev, "PTP event queue overflow\n");
+ ptp->evt_overflow = true;
}
spin_unlock_bh(&ptp->evt_lock);
}