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>

diff --git a/drivers/net/e1000e/e1000.h b/drivers/net/e1000e/e1000.h
index 37bcb19..28bf9a5 100644 (file)
--- 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 2ffd752..e04b392 100644 (file)
--- 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;