e1000e: drop lltx, remove unnecessary lock

LLTX is deprecated and complicated, don't use it.  It was observed by Don Ash
<donash4@gmail.com> that e1000e was acquiring this lock in the NAPI cleanup
path.  This is obviously a bug, as this is a leftover from when e1000
supported multiple tx queues and fake netdevs.

another user reported this to us and tested routing with the 2.6.27 kernel and
this patch and reported a 3.5 % improvement in packets forwarded in a
multi-port test on 82571 parts.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 3 insertions, 33 deletions

diff --git a/drivers/net/e1000e/e1000.h b/drivers/net/e1000e/e1000.h
index 37bcb190eef8..28bf9a51346f 100644
--- a/drivers/net/e1000e/e1000.h
+++ b/drivers/net/e1000e/e1000.h
@@ -195,8 +195,6 @@ struct e1000_adapter {
         u16 link_duplex;
         u16 eeprom_vers;
 
-        spinlock_t tx_queue_lock; /* prevent concurrent tail updates */
-
         /* track device up/down/testing state */
         unsigned long state;
 
diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
index 2ffd7523a91c..e04b392c9a59 100644
--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -47,7 +47,7 @@
 
 #include "e1000.h"
 
-#define DRV_VERSION "0.3.3.3-k6"
+#define DRV_VERSION "0.3.3.4-k2"
 char e1000e_driver_name[] = "e1000e";
 const char e1000e_driver_version[] = DRV_VERSION;
 
@@ -1698,7 +1698,6 @@ int e1000e_setup_tx_resources(struct e1000_adapter *adapter)
 
         tx_ring->next_to_use = 0;
         tx_ring->next_to_clean = 0;
-        spin_lock_init(&adapter->tx_queue_lock);
 
         return 0;
 err:
@@ -2007,16 +2006,7 @@ static int e1000_clean(struct napi_struct *napi, int budget)
             !(adapter->rx_ring->ims_val & adapter->tx_ring->ims_val))
                 goto clean_rx;
 
-        /*
-         * e1000_clean is called per-cpu.  This lock protects
-         * tx_ring from being cleaned by multiple cpus
-         * simultaneously.  A failure obtaining the lock means
-         * tx_ring is currently being cleaned anyway.
-         */
-        if (spin_trylock(&adapter->tx_queue_lock)) {
-                tx_cleaned = e1000_clean_tx_irq(adapter);
-                spin_unlock(&adapter->tx_queue_lock);
-        }
+        tx_cleaned = e1000_clean_tx_irq(adapter);
 
 clean_rx:
         adapter->clean_rx(adapter, &work_done, budget);
@@ -2922,8 +2912,6 @@ static int __devinit e1000_sw_init(struct e1000_adapter *adapter)
         if (e1000_alloc_queues(adapter))
                 return -ENOMEM;
 
-        spin_lock_init(&adapter->tx_queue_lock);
-
         /* Explicitly disable IRQ since the NIC can be in any state. */
         e1000_irq_disable(adapter);
 
@@ -4069,7 +4057,6 @@ static int e1000_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
         unsigned int max_txd_pwr = E1000_MAX_TXD_PWR;
         unsigned int tx_flags = 0;
         unsigned int len = skb->len - skb->data_len;
-        unsigned long irq_flags;
         unsigned int nr_frags;
         unsigned int mss;
         int count = 0;
@@ -4138,18 +4125,12 @@ static int e1000_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
         if (adapter->hw.mac.tx_pkt_filtering)
                 e1000_transfer_dhcp_info(adapter, skb);
 
-        if (!spin_trylock_irqsave(&adapter->tx_queue_lock, irq_flags))
-                /* Collision - tell upper layer to requeue */
-                return NETDEV_TX_LOCKED;
-
         /*
          * need: count + 2 desc gap to keep tail from touching
          * head, otherwise try next time
          */
-        if (e1000_maybe_stop_tx(netdev, count + 2)) {
-                spin_unlock_irqrestore(&adapter->tx_queue_lock, irq_flags);
+        if (e1000_maybe_stop_tx(netdev, count + 2))
                 return NETDEV_TX_BUSY;
-        }
 
         if (adapter->vlgrp && vlan_tx_tag_present(skb)) {
                 tx_flags |= E1000_TX_FLAGS_VLAN;
@@ -4161,7 +4142,6 @@ static int e1000_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
         tso = e1000_tso(adapter, skb);
         if (tso < 0) {
                 dev_kfree_skb_any(skb);
-                spin_unlock_irqrestore(&adapter->tx_queue_lock, irq_flags);
                 return NETDEV_TX_OK;
         }
 
@@ -4182,7 +4162,6 @@ static int e1000_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
         if (count < 0) {
                 /* handle pci_map_single() error in e1000_tx_map */
                 dev_kfree_skb_any(skb);
-                spin_unlock_irqrestore(&adapter->tx_queue_lock, irq_flags);
                 return NETDEV_TX_OK;
         }
 
@@ -4193,7 +4172,6 @@ static int e1000_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
         /* Make sure there is space in the ring for the next send. */
         e1000_maybe_stop_tx(netdev, MAX_SKB_FRAGS + 2);
 
-        spin_unlock_irqrestore(&adapter->tx_queue_lock, irq_flags);
         return NETDEV_TX_OK;
 }
 
@@ -4922,12 +4900,6 @@ static int __devinit e1000_probe(struct pci_dev *pdev,
         if (pci_using_dac)
                 netdev->features |= NETIF_F_HIGHDMA;
 
-        /*
-         * We should not be using LLTX anymore, but we are still Tx faster with
-         * it.
-         */
-        netdev->features |= NETIF_F_LLTX;
-
         if (e1000e_enable_mng_pass_thru(&adapter->hw))
                 adapter->flags |= FLAG_MNG_PT_ENABLED;