ixgb: revert an unwanted fix regarding tso/descriptors

There seemed to be another bug introduced as well as a performance hit
with the addtion of the sentinel descriptor workaround.  Removal of
this workaround appears to prevent the hang.  We'll take a risk
and remove it, as we had never seen the originally reported bug
under linux.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: John Ronciak <john.ronciak@intel.com>

1 files changed, 1 insertions, 14 deletions

diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index 26c777f1f565..5561ab6e9d36 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -1295,7 +1295,6 @@ 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;
@@ -1307,11 +1306,6 @@ 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,
@@ -1337,12 +1331,6 @@ 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,
@@ -1421,8 +1409,7 @@ 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 \
-        /* one more for TSO workaround */ + 1
+        MAX_SKB_FRAGS * TXD_USE_COUNT(PAGE_SIZE) + 1
 
 static int
 ixgb_xmit_frame(struct sk_buff *skb, struct net_device *netdev)