| Message ID | 20170503172904.9788-15-jacob.e.keller@intel.com |
|---|---|
| State | Accepted |
| Delegated to: | Jeff Kirsher |
| Headers | show |
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@lists.osuosl.org] On > Behalf Of Jacob Keller > Sent: Wednesday, May 3, 2017 10:29 AM > To: Intel Wired LAN <intel-wired-lan@lists.osuosl.org> > Cc: Richard Cochran <richardcochran@gmail.com> > Subject: [Intel-wired-lan] [PATCH v4 14/15] igb: check for Tx timestamp > timeouts during watchdog > > The igb driver has logic to handle only one Tx timestamp at a time, > using a state bit lock to avoid multiple requests at once. > > It may be possible, if incredibly unlikely, that a Tx timestamp event is > requested but never completes. Since we use an interrupt scheme to > determine when the Tx timestamp occurred we would never clear the state > bit in this case. > > Add an igb_ptp_tx_hang() function similar to the already existing > igb_ptp_rx_hang() function. This function runs in the watchdog routine > and makes sure we eventually recover from this case instead of > permanently disabling Tx timestamps. > > Note: there is no currently known way to cause this without hacking the > driver code to force it. > > Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> > --- > drivers/net/ethernet/intel/igb/igb.h | 1 + > drivers/net/ethernet/intel/igb/igb_main.c | 1 + > drivers/net/ethernet/intel/igb/igb_ptp.c | 29 > +++++++++++++++++++++++++++++ > 3 files changed, 31 insertions(+) Tested-by: Aaron Brown <aaron.f.brown@intel.com>
diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h index be35edcf6b08..ff4d9073781a 100644 --- a/drivers/net/ethernet/intel/igb/igb.h +++ b/drivers/net/ethernet/intel/igb/igb.h @@ -677,6 +677,7 @@ void igb_ptp_stop(struct igb_adapter *adapter); void igb_ptp_reset(struct igb_adapter *adapter); void igb_ptp_suspend(struct igb_adapter *adapter); void igb_ptp_rx_hang(struct igb_adapter *adapter); +void igb_ptp_tx_hang(struct igb_adapter *adapter); void igb_ptp_rx_rgtstamp(struct igb_q_vector *q_vector, struct sk_buff *skb); void igb_ptp_rx_pktstamp(struct igb_q_vector *q_vector, void *va, struct sk_buff *skb); diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index 21b455bfb4ca..eec54d9df06b 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -4726,6 +4726,7 @@ static void igb_watchdog_task(struct work_struct *work) igb_spoof_check(adapter); igb_ptp_rx_hang(adapter); + igb_ptp_tx_hang(adapter); /* Check LVMMC register on i350/i354 only */ if ((adapter->hw.mac.type == e1000_i350) || diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c index a2da5738bfb5..b2f67c169bd2 100644 --- a/drivers/net/ethernet/intel/igb/igb_ptp.c +++ b/drivers/net/ethernet/intel/igb/igb_ptp.c @@ -711,6 +711,35 @@ void igb_ptp_rx_hang(struct igb_adapter *adapter) } } +/** + * igb_ptp_tx_hang - detect error case where Tx timestamp never finishes + * @adapter: private network adapter structure + */ +void igb_ptp_tx_hang(struct igb_adapter *adapter) +{ + bool timeout = time_is_before_jiffies(adapter->ptp_tx_start + + IGB_PTP_TX_TIMEOUT); + + if (!adapter->ptp_tx_skb) + return; + + if (!test_bit(__IGB_PTP_TX_IN_PROGRESS, &adapter->state)) + return; + + /* If we haven't received a timestamp within the timeout, it is + * reasonable to assume that it will never occur, so we can unlock the + * timestamp bit when this occurs. + */ + if (timeout) { + cancel_work_sync(&adapter->ptp_tx_work); + dev_kfree_skb_any(adapter->ptp_tx_skb); + adapter->ptp_tx_skb = NULL; + clear_bit_unlock(__IGB_PTP_TX_IN_PROGRESS, &adapter->state); + adapter->tx_hwtstamp_timeouts++; + dev_warn(&adapter->pdev->dev, "clearing Tx timestamp hang\n"); + } +} + /** * igb_ptp_tx_hwtstamp - utility function which checks for TX time stamp * @adapter: Board private structure.
The igb driver has logic to handle only one Tx timestamp at a time, using a state bit lock to avoid multiple requests at once. It may be possible, if incredibly unlikely, that a Tx timestamp event is requested but never completes. Since we use an interrupt scheme to determine when the Tx timestamp occurred we would never clear the state bit in this case. Add an igb_ptp_tx_hang() function similar to the already existing igb_ptp_rx_hang() function. This function runs in the watchdog routine and makes sure we eventually recover from this case instead of permanently disabling Tx timestamps. Note: there is no currently known way to cause this without hacking the driver code to force it. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> --- drivers/net/ethernet/intel/igb/igb.h | 1 + drivers/net/ethernet/intel/igb/igb_main.c | 1 + drivers/net/ethernet/intel/igb/igb_ptp.c | 29 +++++++++++++++++++++++++++++ 3 files changed, 31 insertions(+)