1 files changed, 15 insertions, 2 deletions

diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index cfd67d812f0d..13181c4f1d20 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -1266,6 +1266,7 @@ ixgb_tx_map(struct ixgb_adapter *adapter, struct sk_buff *skb,
         struct ixgb_buffer *buffer_info;
         int len = skb->len;
         unsigned int offset = 0, size, count = 0, i;
+        unsigned int mss = skb_shinfo(skb)->tso_size;
 
         unsigned int nr_frags = skb_shinfo(skb)->nr_frags;
         unsigned int f;
@@ -1277,6 +1278,11 @@ ixgb_tx_map(struct ixgb_adapter *adapter, struct sk_buff *skb,
         while(len) {
                 buffer_info = &tx_ring->buffer_info[i];
                 size = min(len, IXGB_MAX_JUMBO_FRAME_SIZE);
+                /* Workaround for premature desc write-backs
+                 * in TSO mode.  Append 4-byte sentinel desc */
+                if(unlikely(mss && !nr_frags && size == len && size > 8))
+                        size -= 4;
+
                 buffer_info->length = size;
                 buffer_info->dma =
                         pci_map_single(adapter->pdev,
@@ -1301,6 +1307,12 @@ ixgb_tx_map(struct ixgb_adapter *adapter, struct sk_buff *skb,
                 while(len) {
                         buffer_info = &tx_ring->buffer_info[i];
                         size = min(len, IXGB_MAX_JUMBO_FRAME_SIZE);
+                        /* Workaround for premature desc write-backs
+                         * in TSO mode.  Append 4-byte sentinel desc */
+                        if(unlikely(mss && (f == (nr_frags-1)) && (size == len)
+                                    && (size > 8)))
+                                size -= 4;
+
                         buffer_info->length = size;
                         buffer_info->dma =
                                 pci_map_page(adapter->pdev,
@@ -1378,7 +1390,8 @@ ixgb_tx_queue(struct ixgb_adapter *adapter, int count, int vlan_id,int tx_flags)
 #define TXD_USE_COUNT(S) (((S) >> IXGB_MAX_TXD_PWR) + \
                          (((S) & (IXGB_MAX_DATA_PER_TXD - 1)) ? 1 : 0))
 #define DESC_NEEDED TXD_USE_COUNT(IXGB_MAX_DATA_PER_TXD) + \
-        MAX_SKB_FRAGS * TXD_USE_COUNT(PAGE_SIZE) + 1
+        MAX_SKB_FRAGS * TXD_USE_COUNT(PAGE_SIZE) + 1 \
+        /* one more for TSO workaround */ + 1
 
 static int
 ixgb_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
@@ -1416,7 +1429,7 @@ ixgb_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
                 return NETDEV_TX_OK;
         }
 
-        if (tso)
+        if (likely(tso))
                 tx_flags |= IXGB_TX_FLAGS_TSO;
         else if(ixgb_tx_csum(adapter, skb))
                 tx_flags |= IXGB_TX_FLAGS_CSUM;