[PATCH] ixgb: Code optimization

Code optimization

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/ixgb/ixgb_main.c net-drivers-2.6/drivers/net/ixgb.new/ixgb_main.c

1 files changed, 12 insertions, 16 deletions

diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index 0a0f0417f85d..db1089c67ebc 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -1822,7 +1822,6 @@ ixgb_clean_rx_irq(struct ixgb_adapter *adapter)
         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 *adapter)
         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 *adapter)
 
                 (*work_done)++;
 #endif
+                status = rx_desc->status;
                 skb = buffer_info->skb;
+
                 prefetch(skb->data);
 
                 if(++i == rx_ring->count) i = 0;
@@ -1864,7 +1867,7 @@ ixgb_clean_rx_irq(struct ixgb_adapter *adapter)
 
                 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 +1875,7 @@ ixgb_clean_rx_irq(struct ixgb_adapter *adapter)
                                          "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 +1884,7 @@ ixgb_clean_rx_irq(struct ixgb_adapter *adapter)
                                 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 +1895,7 @@ ixgb_clean_rx_irq(struct ixgb_adapter *adapter)
 
                 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 +1903,7 @@ ixgb_clean_rx_irq(struct ixgb_adapter *adapter)
                         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 *adapter)
 #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;
         }