From: Jacob Keller jacob.e.keller@intel.com
commit 622a2ef538fb3ca8eccf49716aba8267d6e95a47 upstream.
The ixgbe 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 ixgbe_ptp_tx_hang() function similar to the already existing ixgbe_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 Tested-by: Andrew Bowers andrewx.bowers@intel.com Signed-off-by: Jeff Kirsher jeffrey.t.kirsher@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/intel/ixgbe/ixgbe.h | 1 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 1 drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c | 27 ++++++++++++++++++++++++++ 3 files changed, 29 insertions(+)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h @@ -991,6 +991,7 @@ void ixgbe_ptp_suspend(struct ixgbe_adap void ixgbe_ptp_stop(struct ixgbe_adapter *adapter); void ixgbe_ptp_overflow_check(struct ixgbe_adapter *adapter); void ixgbe_ptp_rx_hang(struct ixgbe_adapter *adapter); +void ixgbe_ptp_tx_hang(struct ixgbe_adapter *adapter); void ixgbe_ptp_rx_pktstamp(struct ixgbe_q_vector *, struct sk_buff *); void ixgbe_ptp_rx_rgtstamp(struct ixgbe_q_vector *, struct sk_buff *skb); static inline void ixgbe_ptp_rx_hwtstamp(struct ixgbe_ring *rx_ring, --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -7258,6 +7258,7 @@ static void ixgbe_service_task(struct wo if (test_bit(__IXGBE_PTP_RUNNING, &adapter->state)) { ixgbe_ptp_overflow_check(adapter); ixgbe_ptp_rx_hang(adapter); + ixgbe_ptp_tx_hang(adapter); }
ixgbe_service_event_complete(adapter); --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c @@ -663,6 +663,33 @@ static void ixgbe_ptp_clear_tx_timestamp }
/** + * ixgbe_ptp_tx_hang - detect error case where Tx timestamp never finishes + * @adapter: private network adapter structure + */ +void ixgbe_ptp_tx_hang(struct ixgbe_adapter *adapter) +{ + bool timeout = time_is_before_jiffies(adapter->ptp_tx_start + + IXGBE_PTP_TX_TIMEOUT); + + if (!adapter->ptp_tx_skb) + return; + + if (!test_bit(__IXGBE_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); + ixgbe_ptp_clear_tx_timestamp(adapter); + adapter->tx_hwtstamp_timeouts++; + e_warn(drv, "clearing Tx timestamp hang\n"); + } +} + +/** * ixgbe_ptp_tx_hwtstamp - utility function which checks for TX time stamp * @adapter: the private adapter struct *