[BRIDGE]: Add support for NETIF_F_HW_CSUM devices

As it is the bridge will only ever declare NETIF_F_IP_CSUM even if all
its constituent devices support NETIF_F_HW_CSUM.  This patch fixes
this by supporting the first one out of NETIF_F_NO_CSUM,
NETIF_F_HW_CSUM, and NETIF_F_IP_CSUM that is supported by all
constituent devices.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/bridge/br_device.c

@@ -145,9 +145,9 @@ static int br_set_tx_csum(struct net_device *dev, u32 data)
 	struct net_bridge *br = netdev_priv(dev);
 
 	if (data)
-		br->feature_mask |= NETIF_F_IP_CSUM;
+		br->feature_mask |= NETIF_F_NO_CSUM;
 	else
-		br->feature_mask &= ~NETIF_F_IP_CSUM;
+		br->feature_mask &= ~NETIF_F_ALL_CSUM;
 
 	br_features_recompute(br);
 	return 0;
@@ -185,5 +185,5 @@ void br_dev_setup(struct net_device *dev)
 	dev->priv_flags = IFF_EBRIDGE;
 
  	dev->features = NETIF_F_SG | NETIF_F_FRAGLIST
- 		| NETIF_F_HIGHDMA | NETIF_F_TSO | NETIF_F_IP_CSUM;
+ 		| NETIF_F_HIGHDMA | NETIF_F_TSO | NETIF_F_NO_CSUM;
 }

net/bridge/br_if.c

@@ -372,11 +372,17 @@ void br_features_recompute(struct net_bridge *br)
 	struct net_bridge_port *p;
 	unsigned long features, checksum;
 
-	features = br->feature_mask &~ NETIF_F_IP_CSUM;
-	checksum = br->feature_mask & NETIF_F_IP_CSUM;
+	checksum = br->feature_mask & NETIF_F_ALL_CSUM ? NETIF_F_NO_CSUM : 0;
+	features = br->feature_mask & ~NETIF_F_ALL_CSUM;
 
 	list_for_each_entry(p, &br->port_list, list) {
-		if (!(p->dev->features & NETIF_F_ALL_CSUM))
+		if (checksum & NETIF_F_NO_CSUM &&
+		    !(p->dev->features & NETIF_F_NO_CSUM))
+			checksum ^= NETIF_F_NO_CSUM | NETIF_F_HW_CSUM;
+		if (checksum & NETIF_F_HW_CSUM &&
+		    !(p->dev->features & NETIF_F_HW_CSUM))
+			checksum ^= NETIF_F_HW_CSUM | NETIF_F_IP_CSUM;
+		if (!(p->dev->features & NETIF_F_IP_CSUM))
 			checksum = 0;
 		features &= p->dev->features;
 	}