e1000e: add timeout for TX HW time stamping work

Hardware may fail to report time stamp e.g.:
 - when hardware time stamping is not enabled
 - when time stamp is requested shortly after ifup

Timeout time stamp reading work to prevent it from
scheduling itself indefinitely. Report timeout events
via system log and device stats.

Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 6bd1832e3f3e..b8d252fcad18 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -1163,6 +1163,12 @@ static void e1000e_tx_hwtstamp_work(struct work_struct *work)
                 skb_tstamp_tx(adapter->tx_hwtstamp_skb, &shhwtstamps);
                 dev_kfree_skb_any(adapter->tx_hwtstamp_skb);
                 adapter->tx_hwtstamp_skb = NULL;
+        } else if (time_after(jiffies, adapter->tx_hwtstamp_start
+                              + adapter->tx_timeout_factor * HZ)) {
+                dev_kfree_skb_any(adapter->tx_hwtstamp_skb);
+                adapter->tx_hwtstamp_skb = NULL;
+                adapter->tx_hwtstamp_timeouts++;
+                e_warn("clearing Tx timestamp hang");
         } else {
                 /* reschedule to check later */
                 schedule_work(&adapter->tx_hwtstamp_work);
@@ -5567,6 +5573,7 @@ static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb,
                         skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
                         tx_flags |= E1000_TX_FLAGS_HWTSTAMP;
                         adapter->tx_hwtstamp_skb = skb_get(skb);
+                        adapter->tx_hwtstamp_start = jiffies;
                         schedule_work(&adapter->tx_hwtstamp_work);
                 } else {
                         skb_tx_timestamp(skb);