[RESEND][PATCH net-drivers-2.6 9/11] ixgb: Code optimization (fwd)

[Malli Chilakala <mallikarjuna.chilakala@xxxxxxxxx>]

Code optimization

Signed-off-by: Mallikarjuna R Chilakala <mallikarjuna.chilakala@xxxxxxxxx>
Signed-off-by: Ganesh Venkatesan <ganesh.venkatesan@xxxxxxxxx>
Signed-off-by: John Ronciak <john.ronciak@xxxxxxxxx>

diff -up net-drivers-2.6/drivers/net/ixgb/ixgb_main.c 
net-drivers-2.6/drivers/net/ixgb.new/ixgb_main.c
--- net-drivers-2.6/drivers/net/ixgb/ixgb_main.c        2005-04-05 
23:06:36.332229456 -0700
+++ net-drivers-2.6/drivers/net/ixgb.new/ixgb_main.c    2005-04-05 
23:06:38.283932752 -0700
@@ -1822,7 +1822,6 @@ ixgb_clean_rx_irq(struct ixgb_adapter *a
        struct pci_dev *pdev = adapter->pdev;
        struct ixgb_rx_desc *rx_desc, *next_rxd;
        struct ixgb_buffer *buffer_info, *next_buffer, *next2_buffer;
-       struct sk_buff *skb, *next_skb;
        uint32_t length;
        unsigned int i, j;
        boolean_t cleaned = FALSE;
@@ -1832,6 +1831,8 @@ ixgb_clean_rx_irq(struct ixgb_adapter *a
        buffer_info = &rx_ring->buffer_info[i];
 
        while(rx_desc->status & IXGB_RX_DESC_STATUS_DD) {
+               struct sk_buff *skb, *next_skb;
+               u8 status;
 
 #ifdef CONFIG_IXGB_NAPI
                if(*work_done >= work_to_do)
@@ -1839,7 +1840,9 @@ ixgb_clean_rx_irq(struct ixgb_adapter *a
 
                (*work_done)++;
 #endif
+               status = rx_desc->status;
                skb = buffer_info->skb;
+
                prefetch(skb->data);
 
                if(++i == rx_ring->count) i = 0;
@@ -1864,7 +1835,7 @@ ixgb_clean_rx_irq(struct ixgb_adapter *a
 
                length = le16_to_cpu(rx_desc->length);
 
-               if(unlikely(!(rx_desc->status & IXGB_RX_DESC_STATUS_EOP))) {
+               if(unlikely(!(status & IXGB_RX_DESC_STATUS_EOP))) {
 
                        /* All receives must fit into a single buffer */
 
@@ -1872,12 +1835,7 @@
                                         "length<%x>\n", length);
 
                        dev_kfree_skb_irq(skb);
-                       rx_desc->status = 0;
-                       buffer_info->skb = NULL;
-
-                       rx_desc = next_rxd;
-                       buffer_info = next_buffer;
-                       continue;
+                       goto rxdesc_done;
                }
 
                if (unlikely(rx_desc->errors
@@ -1886,12 +1835,7 @@
                                IXGB_RX_DESC_ERRORS_RXE))) {
 
                        dev_kfree_skb_irq(skb);
-                       rx_desc->status = 0;
-                       buffer_info->skb = NULL;
-
-                       rx_desc = next_rxd;
-                       buffer_info = next_buffer;
-                       continue;
+                       goto rxdesc_done;
                }
 
                /* Good Receive */
@@ -1902,7 +1879,7 @@ ixgb_clean_rx_irq(struct ixgb_adapter *a
 
                skb->protocol = eth_type_trans(skb, netdev);
 #ifdef CONFIG_IXGB_NAPI
-               if(adapter->vlgrp && (rx_desc->status & 
IXGB_RX_DESC_STATUS_VP)) {
+               if(adapter->vlgrp && (status & IXGB_RX_DESC_STATUS_VP)) {
                        vlan_hwaccel_receive_skb(skb, adapter->vlgrp,
                                le16_to_cpu(rx_desc->special) &
                                        IXGB_RX_DESC_SPECIAL_VLAN_MASK);
@@ -1910,7 +1879,7 @@
                        netif_receive_skb(skb);
                }
 #else /* CONFIG_IXGB_NAPI */
-               if(adapter->vlgrp && (rx_desc->status & 
IXGB_RX_DESC_STATUS_VP)) {
+               if(adapter->vlgrp && (status & IXGB_RX_DESC_STATUS_VP)) {
                        vlan_hwaccel_rx(skb, adapter->vlgrp,
                                le16_to_cpu(rx_desc->special) &
                                        IXGB_RX_DESC_SPECIAL_VLAN_MASK);
@@ -1920,9 +1913,12 @@ ixgb_clean_rx_irq(struct ixgb_adapter *a
 #endif /* CONFIG_IXGB_NAPI */
                netdev->last_rx = jiffies;
 
+rxdesc_done:
+               /* clean up descriptor, might be written over by hw */
                rx_desc->status = 0;
                buffer_info->skb = NULL;
 
+               /* use prefetched values */
                rx_desc = next_rxd;
                buffer_info = next_buffer;
        }