atl1: use csum_start

Use skb->csum_start for tx checksum offload preparation. Also swap
the variables css and cso so they hold the intended values of csum
start and offset, respectively.

Signed-off-by: Jay Cliburn <jacliburn@bellsouth.net>
Acked-by: Chris Snook <csnook@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 6 insertions, 5 deletions

diff --git a/drivers/net/atlx/atl1.c b/drivers/net/atlx/atl1.c
index f4add3cafe24..99298222c8f6 100644
--- a/drivers/net/atlx/atl1.c
+++ b/drivers/net/atlx/atl1.c
@@ -1347,16 +1347,17 @@ static int atl1_tx_csum(struct atl1_adapter *adapter, struct sk_buff *skb,
         u8 css, cso;
 
         if (likely(skb->ip_summed == CHECKSUM_PARTIAL)) {
-                cso = skb_transport_offset(skb);
-                css = cso + skb->csum_offset;
-                if (unlikely(cso & 0x1)) {
+                css = (u8) (skb->csum_start - skb_headroom(skb));
+                cso = css + (u8) skb->csum_offset;
+                if (unlikely(css & 0x1)) {
+                        /* L1 hardware requires an even number here */
                         dev_printk(KERN_DEBUG, &adapter->pdev->dev,
                                 "payload offset not an even number\n");
                         return -1;
                 }
-                ptpd->word3 |= (cso & TPD_PLOADOFFSET_MASK) <<
+                ptpd->word3 |= (css & TPD_PLOADOFFSET_MASK) <<
                         TPD_PLOADOFFSET_SHIFT;
-                ptpd->word3 |= (css & TPD_CCSUMOFFSET_MASK) <<
+                ptpd->word3 |= (cso & TPD_CCSUMOFFSET_MASK) <<
                         TPD_CCSUMOFFSET_SHIFT;
                 ptpd->word3 |= 1 << TPD_CUST_CSUM_EN_SHIFT;
                 return true;