bridge: Simplify pvid checks.

Currently, if the pvid is not set, we return an illegal vlan value
even though the pvid value is set to 0.  Since pvid of 0 is currently
invalid, just return 0 instead.  This makes the current and future
checks simpler.
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_private.h

@@ -643,11 +643,8 @@ static inline int br_vlan_get_tag(const struct sk_buff *skb, u16 *vid)
 
 static inline u16 br_get_pvid(const struct net_port_vlans *v)
 {
-	/* Return just the VID if it is set, or VLAN_N_VID (invalid vid) if
-	 * vid wasn't set
-	 */
 	smp_rmb();
-	return v->pvid ?: VLAN_N_VID;
+	return v->pvid;
 }
 
 static inline int br_vlan_enabled(struct net_bridge *br)
@@ -746,7 +743,7 @@ static inline u16 br_vlan_get_tag(const struct sk_buff *skb, u16 *tag)
 }
 static inline u16 br_get_pvid(const struct net_port_vlans *v)
 {
-	return VLAN_N_VID;	/* Returns invalid vid */
+	return 0;
 }
 
 static inline int br_vlan_enabled(struct net_bridge *br)

net/bridge/br_vlan.c

@@ -223,7 +223,7 @@ bool br_allowed_ingress(struct net_bridge *br, struct net_port_vlans *v,
 		 * See if pvid is set on this port.  That tells us which
 		 * vlan untagged or priority-tagged traffic belongs to.
 		 */
-		if (pvid == VLAN_N_VID)
+		if (!pvid)
 			goto drop;
 
 		/* PVID is set on this port.  Any untagged or priority-tagged
@@ -292,7 +292,7 @@ bool br_should_learn(struct net_bridge_port *p, struct sk_buff *skb, u16 *vid)
 
 	if (!*vid) {
 		*vid = br_get_pvid(v);
-		if (*vid == VLAN_N_VID)
+		if (!*vid)
 			return false;
 
 		return true;