3 files changed, 44 insertions, 33 deletions

diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 5e1892d8d874..0eded176ce99 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -179,5 +179,5 @@ 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_NO_CSUM | NETIF_F_GSO_ROBUST;
+                        NETIF_F_GSO_MASK | NETIF_F_NO_CSUM | NETIF_F_LLTX;
 }
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index b40dada002bf..749f0e8f541d 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -349,43 +349,15 @@ int br_min_mtu(const struct net_bridge *br)
 void br_features_recompute(struct net_bridge *br)
 {
         struct net_bridge_port *p;
-        unsigned long features, checksum;
+        unsigned long features;
 
-        checksum = br->feature_mask & NETIF_F_ALL_CSUM ? NETIF_F_NO_CSUM : 0;
-        features = br->feature_mask & ~NETIF_F_ALL_CSUM;
+        features = br->feature_mask;
 
         list_for_each_entry(p, &br->port_list, list) {
-                unsigned long feature = p->dev->features;
-
-                /* if device needs checksumming, downgrade to hw checksumming */
-                if (checksum & NETIF_F_NO_CSUM && !(feature & NETIF_F_NO_CSUM))
-                        checksum ^= NETIF_F_NO_CSUM | NETIF_F_HW_CSUM;
-
-                /* if device can't do all checksum, downgrade to ipv4/ipv6 */
-                if (checksum & NETIF_F_HW_CSUM && !(feature & NETIF_F_HW_CSUM))
-                        checksum ^= NETIF_F_HW_CSUM
-                                | NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
-
-                if (checksum & NETIF_F_IPV6_CSUM && !(feature & NETIF_F_IPV6_CSUM))
-                        checksum &= ~NETIF_F_IPV6_CSUM;
-
-                if (!(feature & NETIF_F_IP_CSUM))
-                        checksum = 0;
-
-                if (feature & NETIF_F_GSO)
-                        feature |= NETIF_F_GSO_SOFTWARE;
-                feature |= NETIF_F_GSO;
-
-                features &= feature;
+                features = netdev_compute_features(features, p->dev->features);
         }
 
-        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;
+        br->dev->features = features;
 }
 
 /* called with RTNL */
diff --git a/net/core/dev.c b/net/core/dev.c
index 6cc8a70350ac..a76021c71207 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3993,6 +3993,45 @@ static int __init netdev_dma_register(void)
 static int __init netdev_dma_register(void) { return -ENODEV; }
 #endif /* CONFIG_NET_DMA */
 
+/**
+ *      netdev_compute_feature - compute conjunction of two feature sets
+ *      @all: first feature set
+ *      @one: second feature set
+ *
+ *      Computes a new feature set after adding a device with feature set
+ *      @one to the master device with current feature set @all.  Returns
+ *      the new feature set.
+ */
+int netdev_compute_features(unsigned long all, unsigned long one)
+{
+        /* if device needs checksumming, downgrade to hw checksumming */
+        if (all & NETIF_F_NO_CSUM && !(one & NETIF_F_NO_CSUM))
+                all ^= NETIF_F_NO_CSUM | NETIF_F_HW_CSUM;
+
+        /* if device can't do all checksum, downgrade to ipv4/ipv6 */
+        if (all & NETIF_F_HW_CSUM && !(one & NETIF_F_HW_CSUM))
+                all ^= NETIF_F_HW_CSUM
+                        | NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
+
+        if (one & NETIF_F_GSO)
+                one |= NETIF_F_GSO_SOFTWARE;
+        one |= NETIF_F_GSO;
+
+        /* If even one device supports robust GSO, enable it for all. */
+        if (one & NETIF_F_GSO_ROBUST)
+                all |= NETIF_F_GSO_ROBUST;
+
+        all &= one | NETIF_F_LLTX;
+
+        if (!(all & NETIF_F_ALL_CSUM))
+                all &= ~NETIF_F_SG;
+        if (!(all & NETIF_F_SG))
+                all &= ~NETIF_F_GSO_MASK;
+
+        return all;
+}
+EXPORT_SYMBOL(netdev_compute_features);
+
 /*
  *      Initialize the DEV module. At boot time this walks the device list and
  *      unhooks any devices that fail to initialise (normally hardware not