ixgb: remove lltx support and update tx routine

a) kernel developers suggest LLTX is broken and unsafe to use, remove it.
b) remember to pre-stop the queue if we won't have room
c) removing lltx means we can remove our tx lock

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

2 files changed, 1 insertions, 32 deletions

diff --git a/drivers/net/ixgb/ixgb.h b/drivers/net/ixgb/ixgb.h
index 16f9c756aa4..3cec7b98d52 100644
--- a/drivers/net/ixgb/ixgb.h
+++ b/drivers/net/ixgb/ixgb.h
@@ -157,7 +157,6 @@ struct ixgb_adapter {
         u32 part_num;
         u16 link_speed;
         u16 link_duplex;
-        spinlock_t tx_lock;
         struct work_struct tx_timeout_task;
 
         struct timer_list blink_timer;
diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index 79082eb577c..bd08e199214 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -448,9 +448,6 @@ ixgb_probe(struct pci_dev *pdev,
                            NETIF_F_HW_VLAN_RX |
                            NETIF_F_HW_VLAN_FILTER;
         netdev->features |= NETIF_F_TSO;
-#ifdef NETIF_F_LLTX
-        netdev->features |= NETIF_F_LLTX;
-#endif
 
         if(pci_using_dac)
                 netdev->features |= NETIF_F_HIGHDMA;
@@ -577,8 +574,6 @@ ixgb_sw_init(struct ixgb_adapter *adapter)
         /* enable flow control to be programmed */
         hw->fc.send_xon = 1;
 
-        spin_lock_init(&adapter->tx_lock);
-
         set_bit(__IXGB_DOWN, &adapter->flags);
         return 0;
 }
@@ -1441,7 +1436,6 @@ ixgb_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
         struct ixgb_adapter *adapter = netdev_priv(netdev);
         unsigned int first;
         unsigned int tx_flags = 0;
-        unsigned long flags;
         int vlan_id = 0;
         int tso;
 
@@ -1455,26 +1449,9 @@ ixgb_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
                 return 0;
         }
 
-#ifdef NETIF_F_LLTX
-        if (!spin_trylock_irqsave(&adapter->tx_lock, flags)) {
-                /* Collision - tell upper layer to requeue */
-                local_irq_restore(flags);
-                return NETDEV_TX_LOCKED;
-        }
-#else
-        spin_lock_irqsave(&adapter->tx_lock, flags);
-#endif
-
         if (unlikely(ixgb_maybe_stop_tx(netdev, &adapter->tx_ring,
-                     DESC_NEEDED))) {
-                netif_stop_queue(netdev);
-                spin_unlock_irqrestore(&adapter->tx_lock, flags);
+                     DESC_NEEDED)))
                 return NETDEV_TX_BUSY;
-        }
-
-#ifndef NETIF_F_LLTX
-        spin_unlock_irqrestore(&adapter->tx_lock, flags);
-#endif
 
         if(adapter->vlgrp && vlan_tx_tag_present(skb)) {
                 tx_flags |= IXGB_TX_FLAGS_VLAN;
@@ -1486,9 +1463,6 @@ ixgb_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
         tso = ixgb_tso(adapter, skb);
         if (tso < 0) {
                 dev_kfree_skb_any(skb);
-#ifdef NETIF_F_LLTX
-                spin_unlock_irqrestore(&adapter->tx_lock, flags);
-#endif
                 return NETDEV_TX_OK;
         }
 
@@ -1502,13 +1476,9 @@ ixgb_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
 
         netdev->trans_start = jiffies;
 
-#ifdef NETIF_F_LLTX
         /* Make sure there is space in the ring for the next send. */
         ixgb_maybe_stop_tx(netdev, &adapter->tx_ring, DESC_NEEDED);
 
-        spin_unlock_irqrestore(&adapter->tx_lock, flags);
-
-#endif
         return NETDEV_TX_OK;
 }