[PATCH 1/1] ixgbe: protect TX timestamping from API misuse

[Manjunath Patil <manjunath.b.patil@oracle.com>]

HW timestamping can only be requested for a packet if the NIC is first
setup via ioctl(SIOCSHWTSTAMP). If this step was skipped, then the ixgbe
driver still allowed TX packets to request HW timestamping. In this
situation, we see 'clearing Tx Timestamp hang' noise in the log.

Fix this by checking that the NIC is configured for HW TX timestamping
before accepting a HW TX timestamping request.

similar-to:
	(26bd4e2 igb: protect TX timestamping from API misuse)
	(0a6f2f0 igb: Fix a test with HWTSTAMP_TX_ON)

Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 1ce2397..dd24aeb 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -8640,7 +8640,8 @@ netdev_tx_t ixgbe_xmit_frame_ring(struct sk_buff *skb,
 
 	if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) &&
 	    adapter->ptp_clock) {
-		if (!test_and_set_bit_lock(__IXGBE_PTP_TX_IN_PROGRESS,
+		if (adapter->tstamp_config.tx_type == HWTSTAMP_TX_ON &&
+		    !test_and_set_bit_lock(__IXGBE_PTP_TX_IN_PROGRESS,
 					   &adapter->state)) {
 			skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
 			tx_flags |= IXGBE_TX_FLAGS_TSTAMP;
-- 
1.7.1