vxlan: Add vxlan_fdb_clear_offload()

When a driver unoffloads all FDB entries en bloc, it's inefficient to
send the switchdev notification one by one. Add a helper that walks the
FDB table, unsetting the offload flag on RDST with a given VNI.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vxlan.c

@@ -599,6 +599,28 @@ int vxlan_fdb_replay(const struct net_device *dev, __be32 vni,
 }
 EXPORT_SYMBOL_GPL(vxlan_fdb_replay);
 
+void vxlan_fdb_clear_offload(const struct net_device *dev, __be32 vni)
+{
+	struct vxlan_dev *vxlan;
+	struct vxlan_rdst *rdst;
+	struct vxlan_fdb *f;
+	unsigned int h;
+
+	if (!netif_is_vxlan(dev))
+		return;
+	vxlan = netdev_priv(dev);
+
+	spin_lock_bh(&vxlan->hash_lock);
+	for (h = 0; h < FDB_HASH_SIZE; ++h) {
+		hlist_for_each_entry(f, &vxlan->fdb_head[h], hlist)
+			if (f->vni == vni)
+				list_for_each_entry(rdst, &f->remotes, list)
+					rdst->offloaded = false;
+	}
+	spin_unlock_bh(&vxlan->hash_lock);
+}
+EXPORT_SYMBOL_GPL(vxlan_fdb_clear_offload);
+
 /* Replace destination of unicast mac */
 static int vxlan_fdb_replace(struct vxlan_fdb *f,
 			     union vxlan_addr *ip, __be16 port, __be32 vni,

include/net/vxlan.h

@@ -429,6 +429,7 @@ int vxlan_fdb_find_uc(struct net_device *dev, const u8 *mac, __be32 vni,
 		      struct switchdev_notifier_vxlan_fdb_info *fdb_info);
 int vxlan_fdb_replay(const struct net_device *dev, __be32 vni,
 		     struct notifier_block *nb);
+void vxlan_fdb_clear_offload(const struct net_device *dev, __be32 vni);
 
 #else
 static inline int
@@ -443,6 +444,11 @@ static inline int vxlan_fdb_replay(const struct net_device *dev, __be32 vni,
 {
 	return -EOPNOTSUPP;
 }
+
+static inline void
+vxlan_fdb_clear_offload(const struct net_device *dev, __be32 vni)
+{
+}
 #endif
 
 #endif