1 files changed, 16 insertions, 2 deletions

diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index e628126c9c49..70ac9d4a83bb 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -1287,6 +1287,7 @@ 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)->gso_size;
 
         unsigned int nr_frags = skb_shinfo(skb)->nr_frags;
         unsigned int f;
@@ -1298,6 +1299,11 @@ 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_DATA_PER_TXD);
+                /* 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;
                 WARN_ON(buffer_info->dma != 0);
                 buffer_info->dma =
@@ -1324,6 +1330,13 @@ 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_DATA_PER_TXD);
+
+                        /* 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_page(adapter->pdev,
@@ -1401,8 +1414,9 @@ ixgb_tx_queue(struct ixgb_adapter *adapter, int count, int vlan_id,int tx_flags)
 /* Tx Descriptors needed, worst case */
 #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
+#define DESC_NEEDED TXD_USE_COUNT(IXGB_MAX_DATA_PER_TXD) /* skb->date */ + \
+        MAX_SKB_FRAGS * TXD_USE_COUNT(PAGE_SIZE) + 1 /* for context */ \
+        + 1 /* one more needed for sentinel TSO workaround */
 
 static int
 ixgb_xmit_frame(struct sk_buff *skb, struct net_device *netdev)