[PATCH] e1000: Delay clean-up of last Tx packet

Delay clean-up of last Tx packet to fix pre-mature writeback issue of Tx descriptors only when TSO is enabled
Signed-off-by: Mallikarjuna R Chilakala <mallikarjuna.chilakala@intel.com>
Signed-off-by: Ganesh Venkatesan <ganesh.venkatesan@intel.com>
Signed-off-by: John Ronciak <john.ronciak@intel.com>
diff -up net-drivers-2.6/drivers/net/e1000/e1000_main.c net-drivers-2.6/drivers/net/e1000.new/e1000_main.c

drivers/net/e1000/e1000_main.c

@@ -2384,9 +2384,8 @@ e1000_clean_tx_irq(struct e1000_adapter *adapter)
 	eop_desc = E1000_TX_DESC(*tx_ring, eop);
 
 	while(eop_desc->upper.data & cpu_to_le32(E1000_TXD_STAT_DD)) {
-		/* pre-mature writeback of Tx descriptors     */
-		/* clear (free buffers and unmap pci_mapping) */
-		/* previous_buffer_info                       */
+		/* Premature writeback of Tx descriptors clear (free buffers
+		 * and unmap pci_mapping) previous_buffer_info */
 		if (likely(adapter->previous_buffer_info.skb != NULL)) {
 			e1000_unmap_and_free_tx_resource(adapter,
 					&adapter->previous_buffer_info);
@@ -2397,20 +2396,25 @@ e1000_clean_tx_irq(struct e1000_adapter *adapter)
 			buffer_info = &tx_ring->buffer_info[i];
 			cleaned = (i == eop);
 
-			/* pre-mature writeback of Tx descriptors */
-			/* save the cleaning of the this for the  */
-			/* next iteration                         */
+#ifdef NETIF_F_TSO
+			if (!(netdev->features & NETIF_F_TSO)) {
+#endif
+				e1000_unmap_and_free_tx_resource(adapter,
+				                                 buffer_info);
+#ifdef NETIF_F_TSO
+			} else {
 				if (cleaned) {
 					memcpy(&adapter->previous_buffer_info,
 					       buffer_info,
 					       sizeof(struct e1000_buffer));
-				memset(buffer_info,
-					0,
+					memset(buffer_info, 0,
 					       sizeof(struct e1000_buffer));
 				} else {
-				e1000_unmap_and_free_tx_resource(adapter, 
-							buffer_info);
+					e1000_unmap_and_free_tx_resource(
+					    adapter, buffer_info);
 				}
+			}
+#endif
 
 			tx_desc->buffer_addr = 0;
 			tx_desc->lower.data = 0;
@@ -2443,7 +2447,14 @@ e1000_clean_tx_irq(struct e1000_adapter *adapter)
 		   !(E1000_READ_REG(&adapter->hw, STATUS) & E1000_STATUS_TXOFF))
 			netif_stop_queue(netdev);
 	}
+#ifdef NETIF_F_TSO
+
+	if( unlikely(!(eop_desc->upper.data & cpu_to_le32(E1000_TXD_STAT_DD)) &&
+	    time_after(jiffies, adapter->previous_buffer_info.time_stamp + HZ)))
+		e1000_unmap_and_free_tx_resource(
+		    adapter, &adapter->previous_buffer_info);
 
+#endif
 	return cleaned;
 }