net: fix netdev_increment_features()

Simplify and fix netdev_increment_features() to conform to what is
stated in netdevice.h comments about NETIF_F_ONE_FOR_ALL.
Include FCoE segmentation and VLAN-challedged flags in computation.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -1106,7 +1106,12 @@ struct net_device {
 	 */
 #define NETIF_F_ONE_FOR_ALL	(NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ROBUST | \
 				 NETIF_F_SG | NETIF_F_HIGHDMA |		\
-				 NETIF_F_FRAGLIST)
+				 NETIF_F_FRAGLIST | NETIF_F_VLAN_CHALLENGED)
+	/*
+	 * If one device doesn't support one of these features, then disable it
+	 * for all in netdev_increment_features.
+	 */
+#define NETIF_F_ALL_FOR_ALL	(NETIF_F_NOCACHE_COPY | NETIF_F_FSO)
 
 	/* changeable features with no special hardware requirements */
 #define NETIF_F_SOFT_FEATURES	(NETIF_F_GSO | NETIF_F_GRO)

net/core/dev.c

@@ -6164,33 +6164,20 @@ static int dev_cpu_callback(struct notifier_block *nfb,
  */
 u32 netdev_increment_features(u32 all, u32 one, u32 mask)
 {
-	/* If device needs checksumming, downgrade to it. */
-	if (all & NETIF_F_NO_CSUM && !(one & NETIF_F_NO_CSUM))
-		all ^= NETIF_F_NO_CSUM | (one & NETIF_F_ALL_CSUM);
-	else if (mask & NETIF_F_ALL_CSUM) {
-		/* If one device supports v4/v6 checksumming, set for all. */
-		if (one & (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM) &&
-		    !(all & NETIF_F_GEN_CSUM)) {
-			all &= ~NETIF_F_ALL_CSUM;
-			all |= one & (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM);
-		}
-
-		/* If one device supports hw checksumming, set for all. */
-		if (one & NETIF_F_GEN_CSUM && !(all & NETIF_F_GEN_CSUM)) {
-			all &= ~NETIF_F_ALL_CSUM;
-			all |= NETIF_F_HW_CSUM;
-		}
-	}
+	if (mask & NETIF_F_GEN_CSUM)
+		mask |= NETIF_F_ALL_CSUM;
+	mask |= NETIF_F_VLAN_CHALLENGED;
 
-	/* If device can't no cache copy, don't do for all */
-	if (!(one & NETIF_F_NOCACHE_COPY))
-		all &= ~NETIF_F_NOCACHE_COPY;
+	all |= one & (NETIF_F_ONE_FOR_ALL|NETIF_F_ALL_CSUM) & mask;
+	all &= one | ~NETIF_F_ALL_FOR_ALL;
 
-	one |= NETIF_F_ALL_CSUM;
+	/* If device needs checksumming, downgrade to it. */
+	if (all & (NETIF_F_ALL_CSUM & ~NETIF_F_NO_CSUM))
+		all &= ~NETIF_F_NO_CSUM;
 
-	one |= all & NETIF_F_ONE_FOR_ALL;
-	all &= one | NETIF_F_LLTX | NETIF_F_GSO | NETIF_F_UFO;
-	all |= one & mask & NETIF_F_ONE_FOR_ALL;
+	/* If one device supports hw checksumming, set for all. */
+	if (all & NETIF_F_GEN_CSUM)
+		all &= ~(NETIF_F_ALL_CSUM & ~NETIF_F_GEN_CSUM);
 
 	return all;
 }