From c2ac3ef35c44195ca2b9c29275c7c6830eb2d9aa Mon Sep 17 00:00:00 2001
From: Jay Cliburn <jacliburn@bellsouth.net>
Date: Mon, 4 Aug 2008 19:05:10 -0500
Subject: [PATCH] atl1: deal with hardware rx checksum bug
The L1 hardware contains a bug that flags a fragmented IP packet
as having an incorrect TCP/UDP checksum, even though the packet
is perfectly valid and its checksum is correct. There's no way to
distinguish between one of these good packets and a packet that
actually contains a TCP/UDP checksum error, so all we can do is
allow the packet to be handed up to the higher layers and let it
be sorted out there.
Add a comment describing this condition and remove the code that
currently fails to handle what may or may not be a checksum error.
Signed-off-by: Jay Cliburn <jacliburn@bellsouth.net>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
---
drivers/net/atlx/atl1.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/drivers/net/atlx/atl1.c b/drivers/net/atlx/atl1.c
index f12e3d12474b..e6a7bb79d4df 100644
--- a/drivers/net/atlx/atl1.c
+++ b/drivers/net/atlx/atl1.c
@@ -1790,6 +1790,17 @@ static void atl1_rx_checksum(struct atl1_adapter *adapter,
{
struct pci_dev *pdev = adapter->pdev;
+ /*
+ * The L1 hardware contains a bug that erroneously sets the
+ * PACKET_FLAG_ERR and ERR_FLAG_L4_CHKSUM bits whenever a
+ * fragmented IP packet is received, even though the packet
+ * is perfectly valid and its checksum is correct. There's
+ * no way to distinguish between one of these good packets
+ * and a packet that actually contains a TCP/UDP checksum
+ * error, so all we can do is allow it to be handed up to
+ * the higher layers and let it be sorted out there.
+ */
+
skb->ip_summed = CHECKSUM_NONE;
if (unlikely(rrd->pkt_flg & PACKET_FLAG_ERR)) {
@@ -1816,14 +1827,6 @@ static void atl1_rx_checksum(struct atl1_adapter *adapter,
return;
}
- /* IPv4, but hardware thinks its checksum is wrong */
- if (netif_msg_rx_err(adapter))
- dev_printk(KERN_DEBUG, &pdev->dev,
- "hw csum wrong, pkt_flag:%x, err_flag:%x\n",
- rrd->pkt_flg, rrd->err_flg);
- skb->ip_summed = CHECKSUM_COMPLETE;
- skb->csum = htons(rrd->xsz.xsum_sz.rx_chksum);
- adapter->hw_csum_err++;
return;
}
--
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