Subject: TSOv6 broken in atl1e

From: Ben Hutchings <[email-masked]>
Date: Tue, 01 Dec 2009 03:19:39 +0000

I received a bug report <http://bugs.debian.org/558426> that shows atl1e
corrupting IPv6 packets.  I have reproduced this on an Eee PC 901 and
found that it is linked to TSO.  The most obvious thing wrong with the
driver code is that it calculates the super-packet length incorrectly.
However, fixing that:

--- a/drivers/net/atl1e/atl1e_main.c
+++ b/drivers/net/atl1e/atl1e_main.c
@@ -1667,6 +1667,7 @@ static int atl1e_tso_csum(struct atl1e_adapter *adapter,
 
 		if (offload_type & SKB_GSO_TCPV6) {
 			real_len = (((unsigned char *)ipv6_hdr(skb) - skb->data)
+					+ sizeof(struct ipv6hdr)
 					+ ntohs(ipv6_hdr(skb)->payload_len));
 			if (real_len < skb->len)
 				pskb_trim(skb, real_len);
--- END ---

does not solve the problem.  Presumably this function is not
constructing correct DMA descriptors for TSOv6.

Please fix this, or I will submit a patch to remove this feature from
the driver.

Ben.

-- 
Ben Hutchings
Quantity is no substitute for quality, but it's the only one we've got.