[BRIDGE]: Disable SG/GSO if TX checksum is off

When the bridge recomputes features, it does not maintain the
constraint that SG/GSO must be off if TX checksum is off.
This patch adds that constraint.

On a completely unrelated note, I've also added TSO6 and TSO_ECN
feature bits if GSO is enabled on the underlying device through
the new NETIF_F_GSO_SOFTWARE macro.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index f55ef68..b1211d534 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -386,12 +386,17 @@
 			checksum = 0;
 
 		if (feature & NETIF_F_GSO)
-			feature |= NETIF_F_TSO;
+			feature |= NETIF_F_GSO_SOFTWARE;
 		feature |= NETIF_F_GSO;
 
 		features &= feature;
 	}
 
+	if (!(checksum & NETIF_F_ALL_CSUM))
+		features &= ~NETIF_F_SG;
+	if (!(features & NETIF_F_SG))
+		features &= ~NETIF_F_GSO_MASK;
+
 	br->dev->features = features | checksum | NETIF_F_LLTX |
 			    NETIF_F_GSO_ROBUST;
 }