From: Cliff Spradlin <cspradlin@google.com>
Date: Mon, 19 Jun 2017 13:30:43 -0700
Subject: igb: protect TX timestamping from API misuse
Patch-mainline: v4.14-rc1
Git-commit: 26bd4e2db06be8a367cba076c6600b4d5c3e65af
References: bsc#1056651 FATE#322191 bsc#1056643 FATE#322192

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 igb
driver still allowed TX packets to request HW timestamping. In this
situation, the _IGB_PTP_TX_IN_PROGRESS flag was set and would never
clear. This prevented any future HW timestamping requests to succeed.

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

Signed-off-by: Cliff Spradlin <cspradlin@google.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Benjamin Poirier <bpoirier@suse.com>
---
 drivers/net/ethernet/intel/igb/igb_main.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -5380,7 +5380,8 @@ netdev_tx_t igb_xmit_frame_ring(struct s
 	if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) {
 		struct igb_adapter *adapter = netdev_priv(tx_ring->netdev);
 
-		if (!test_and_set_bit_lock(__IGB_PTP_TX_IN_PROGRESS,
+		if (adapter->tstamp_config.tx_type & HWTSTAMP_TX_ON &&
+		    !test_and_set_bit_lock(__IGB_PTP_TX_IN_PROGRESS,
 					   &adapter->state)) {
 			skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
 			tx_flags |= IGB_TX_FLAGS_TSTAMP;