vlan: Introduce helper functions to check if skb is tagged

Separate the two checks for single vlan and multiple vlans in
netif_skb_features().  This allows us to move the check for multiple
vlans to another function later.

Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 16 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index a0408d497dae..04bffcd4a48d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2567,7 +2567,6 @@ netdev_features_t netif_skb_features(struct sk_buff *skb)
         struct net_device *dev = skb->dev;
         netdev_features_t features = dev->features;
         u16 gso_segs = skb_shinfo(skb)->gso_segs;
-        __be16 protocol = skb->protocol;
 
         if (gso_segs > dev->gso_max_segs || gso_segs < dev->gso_min_segs)
                 features &= ~NETIF_F_GSO_MASK;
@@ -2579,22 +2578,15 @@ netdev_features_t netif_skb_features(struct sk_buff *skb)
         if (skb->encapsulation)
                 features &= dev->hw_enc_features;
 
-        if (!skb_vlan_tag_present(skb)) {
-                if (unlikely(protocol == htons(ETH_P_8021Q) ||
-                             protocol == htons(ETH_P_8021AD))) {
-                        struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data;
-                        protocol = veh->h_vlan_encapsulated_proto;
-                } else {
-                        goto finalize;
-                }
-        }
-
-        features = netdev_intersect_features(features,
-                                             dev->vlan_features |
-                                             NETIF_F_HW_VLAN_CTAG_TX |
-                                             NETIF_F_HW_VLAN_STAG_TX);
+        if (skb_vlan_tagged(skb))
+                features = netdev_intersect_features(features,
+                                                     dev->vlan_features |
+                                                     NETIF_F_HW_VLAN_CTAG_TX |
+                                                     NETIF_F_HW_VLAN_STAG_TX);
+        else
+                goto finalize;
 
-        if (protocol == htons(ETH_P_8021Q) || protocol == htons(ETH_P_8021AD))
+        if (skb_vlan_tagged_multi(skb))
                 features = netdev_intersect_features(features,
                                                      NETIF_F_SG |
                                                      NETIF_F_HIGHDMA |