From: Jacob Keller <jacob.e.keller@intel.com>
Date: Wed, 3 May 2017 10:28:55 -0700
Subject: igb: avoid permanent lock of *_PTP_TX_IN_PROGRESS
Patch-mainline: v4.13-rc1
Git-commit: 74344e32fcc0d09342b77ed9d23ea74b3799d157
References: bsc#1056651 FATE#322191 bsc#1056643 FATE#322192

The igb driver uses a state bit lock to avoid handling more than one Tx
timestamp request at once. This is required because hardware is limited
to a single set of registers for Tx timestamps.

The state bit lock is not properly cleaned up during
igb_xmit_frame_ring() if the transmit fails such as due to DMA or TSO
failure. In some hardware this results in blocking timestamps until the
service task times out. In other hardware this results in a permanent
lock of the timestamp bit because we never receive an interrupt
indicating the timestamp occurred, since indeed the packet was never
transmitted.

Fix this by checking for DMA and TSO errors in igb_xmit_frame_ring() and
properly cleaning up after ourselves when these occur.

Reported-by: Reported-by: David Mirabito <davidm@metamako.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.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 |   23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -5197,9 +5197,9 @@ static inline int igb_maybe_stop_tx(stru
 	return __igb_maybe_stop_tx(tx_ring, size);
 }
 
-static void igb_tx_map(struct igb_ring *tx_ring,
-		       struct igb_tx_buffer *first,
-		       const u8 hdr_len)
+static int igb_tx_map(struct igb_ring *tx_ring,
+		      struct igb_tx_buffer *first,
+		      const u8 hdr_len)
 {
 	struct sk_buff *skb = first->skb;
 	struct igb_tx_buffer *tx_buffer;
@@ -5310,7 +5310,7 @@ static void igb_tx_map(struct igb_ring *
 		 */
 		mmiowb();
 	}
-	return;
+	return 0;
 
 dma_error:
 	dev_err(tx_ring->dev, "TX DMA map failed\n");
@@ -5341,6 +5341,8 @@ dma_error:
 	tx_buffer->skb = NULL;
 
 	tx_ring->next_to_use = i;
+
+	return -1;
 }
 
 netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
@@ -5406,13 +5408,24 @@ netdev_tx_t igb_xmit_frame_ring(struct s
 	else if (!tso)
 		igb_tx_csum(tx_ring, first);
 
-	igb_tx_map(tx_ring, first, hdr_len);
+	if (igb_tx_map(tx_ring, first, hdr_len))
+		goto cleanup_tx_tstamp;
 
 	return NETDEV_TX_OK;
 
 out_drop:
 	dev_kfree_skb_any(first->skb);
 	first->skb = NULL;
+cleanup_tx_tstamp:
+	if (unlikely(tx_flags & IGB_TX_FLAGS_TSTAMP)) {
+		struct igb_adapter *adapter = netdev_priv(tx_ring->netdev);
+
+		dev_kfree_skb_any(adapter->ptp_tx_skb);
+		adapter->ptp_tx_skb = NULL;
+		if (adapter->hw.mac.type == e1000_82576)
+			cancel_work_sync(&adapter->ptp_tx_work);
+		clear_bit_unlock(__IGB_PTP_TX_IN_PROGRESS, &adapter->state);
+	}
 
 	return NETDEV_TX_OK;
 }