[PATCH] [215/223] r8169: fix rx checksum offload

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Eric Dumazet <eric.dumazet@xxxxxxxxx>

commit adea1ac7effbddbe60a9de6d63462bfe79289e59 upstream.

While porting GRO to r8169, I found this driver has a bug in its rx
path.

All skbs given to network stack had their ip_summed set to
CHECKSUM_NONE, while hardware said they had correct TCP/UDP checksums.

The reason is driver sets skb->ip_summed on the original skb before the
copy eventually done by copybreak. The fresh skb gets the ip_summed =
CHECKSUM_NONE value, forcing network stack to recompute checksum, and
preventing my GRO patch to work.

Fix is to make the ip_summed setting after skb copy.

Note : rx_copybreak current value is 16383, so all frames are copied...

Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Acked-by: Francois Romieu <romieu@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

---
 drivers/net/r8169.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

Index: linux/drivers/net/r8169.c
===================================================================
--- linux.orig/drivers/net/r8169.c
+++ linux/drivers/net/r8169.c
@@ -4458,9 +4458,8 @@ static inline int rtl8169_fragmented_fra
 	return (status & (FirstFrag | LastFrag)) != (FirstFrag | LastFrag);
 }
 
-static inline void rtl8169_rx_csum(struct sk_buff *skb, struct RxDesc *desc)
+static inline void rtl8169_rx_csum(struct sk_buff *skb, u32 opts1)
 {
-	u32 opts1 = le32_to_cpu(desc->opts1);
 	u32 status = opts1 & RxProtoMask;
 
 	if (((status == RxProtoTCP) && !(opts1 & TCPFail)) ||
@@ -4554,8 +4553,6 @@ static int rtl8169_rx_interrupt(struct n
 				continue;
 			}
 
-			rtl8169_rx_csum(skb, desc);
-
 			if (rtl8169_try_rx_copy(&skb, tp, pkt_size, addr)) {
 				pci_dma_sync_single_for_device(pdev, addr,
 					pkt_size, PCI_DMA_FROMDEVICE);
@@ -4566,6 +4563,7 @@ static int rtl8169_rx_interrupt(struct n
 				tp->Rx_skbuff[entry] = NULL;
 			}
 
+			rtl8169_rx_csum(skb, status);
 			skb_put(skb, pkt_size);
 			skb->protocol = eth_type_trans(skb, dev);
 
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