tg3: Work around HW/FW limitations with vlan encapsulated frames

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>

1 files changed, 18 insertions, 2 deletions

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index cb77ae93d89a..e7d3a620d96a 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -7914,8 +7914,6 @@ static netdev_tx_t tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
         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) {
@@ -7929,6 +7927,13 @@ static netdev_tx_t tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
                 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, tnapi, txq, skb);
+
                 if (!skb_is_gso_v6(skb)) {
                         if (unlikely((ETH_HLEN + hdr_len) > 80) &&
                             tg3_flag(tp, TSO_BUG))
@@ -7979,6 +7984,17 @@ static netdev_tx_t tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
                                 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) &&