[PATCH 3.10 07/16] tg3: Work around HW/FW limitations with vlan encapsulated frames

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Vlad Yasevich <vyasevich@gmail.com>

[ Upstream commit 476c18850c6cbaa3f2bb661ae9710645081563b9 ]

TG3 appears to have an issue performing TSO and checksum offloading
correclty when the frame has been vlan encapsulated (non-accelrated).
In these cases, tcp checksum is not correctly updated.

This patch attempts to work around this issue.  After the patch,
802.1ad vlans start working correctly over tg3 devices.

CC: Prashant Sreedharan <prashant@broadcom.com>
CC: Michael Chan <mchan@broadcom.com>
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/broadcom/tg3.c |   20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -7759,8 +7759,6 @@ static netdev_tx_t tg3_start_xmit(struct
 
 	entry = tnapi->tx_prod;
 	base_flags = 0;
-	if (skb->ip_summed == CHECKSUM_PARTIAL)
-		base_flags |= TXD_FLAG_TCPUDP_CSUM;
 
 	mss = skb_shinfo(skb)->gso_size;
 	if (mss) {
@@ -7776,6 +7774,13 @@ static netdev_tx_t tg3_start_xmit(struct
 
 		hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb) - ETH_HLEN;
 
+		/* HW/FW can not correctly segment packets that have been
+		 * vlan encapsulated.
+		 */
+		if (skb->protocol == htons(ETH_P_8021Q) ||
+		    skb->protocol == htons(ETH_P_8021AD))
+			return tg3_tso_bug(tp, skb);
+
 		if (!skb_is_gso_v6(skb)) {
 			iph->check = 0;
 			iph->tot_len = htons(mss + hdr_len);
@@ -7822,6 +7827,17 @@ static netdev_tx_t tg3_start_xmit(struct
 				base_flags |= tsflags << 12;
 			}
 		}
+	} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
+		/* HW/FW can not correctly checksum packets that have been
+		 * vlan encapsulated.
+		 */
+		if (skb->protocol == htons(ETH_P_8021Q) ||
+		    skb->protocol == htons(ETH_P_8021AD)) {
+			if (skb_checksum_help(skb))
+				goto drop;
+		} else  {
+			base_flags |= TXD_FLAG_TCPUDP_CSUM;
+		}
 	}
 
 	if (tg3_flag(tp, USE_JUMBO_BDFLAG) &&