vxlan: add new fdb alloc and create helpers

- Add new vxlan_fdb_alloc helper
- rename existing vxlan_fdb_create into vxlan_fdb_update:
        because it really creates or updates an existing
        fdb entry
- move new fdb creation into a separate vxlan_fdb_create

Main motivation for this change is to introduce the ability
to decouple vxlan fdb creation and notify, used in a later patch.
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vxlan.c

@@ -636,8 +636,61 @@ static int vxlan_gro_complete(struct sock *sk, struct sk_buff *skb, int nhoff)
 	return eth_gro_complete(skb, nhoff + sizeof(struct vxlanhdr));
 }
 
-/* Add new entry to forwarding table -- assumes lock held */
+static struct vxlan_fdb *vxlan_fdb_alloc(struct vxlan_dev *vxlan,
+					 const u8 *mac, __u16 state,
+					 __be32 src_vni, __u8 ndm_flags)
+{
+	struct vxlan_fdb *f;
+
+	f = kmalloc(sizeof(*f), GFP_ATOMIC);
+	if (!f)
+		return NULL;
+	f->state = state;
+	f->flags = ndm_flags;
+	f->updated = f->used = jiffies;
+	f->vni = src_vni;
+	INIT_LIST_HEAD(&f->remotes);
+	memcpy(f->eth_addr, mac, ETH_ALEN);
+
+	return f;
+}
+
 static int vxlan_fdb_create(struct vxlan_dev *vxlan,
+			    const u8 *mac, union vxlan_addr *ip,
+			    __u16 state, __be16 port, __be32 src_vni,
+			    __be32 vni, __u32 ifindex, __u8 ndm_flags,
+			    struct vxlan_fdb **fdb)
+{
+	struct vxlan_rdst *rd = NULL;
+	struct vxlan_fdb *f;
+	int rc;
+
+	if (vxlan->cfg.addrmax &&
+	    vxlan->addrcnt >= vxlan->cfg.addrmax)
+		return -ENOSPC;
+
+	netdev_dbg(vxlan->dev, "add %pM -> %pIS\n", mac, ip);
+	f = vxlan_fdb_alloc(vxlan, mac, state, src_vni, ndm_flags);
+	if (!f)
+		return -ENOMEM;
+
+	rc = vxlan_fdb_append(f, ip, port, vni, ifindex, &rd);
+	if (rc < 0) {
+		kfree(f);
+		return rc;
+	}
+
+	++vxlan->addrcnt;
+	hlist_add_head_rcu(&f->hlist,
+			   vxlan_fdb_head(vxlan, mac, src_vni));
+
+	*fdb = f;
+
+	return 0;
+}
+
+/* Add new entry to forwarding table -- assumes lock held */
+static int vxlan_fdb_update(struct vxlan_dev *vxlan,
 			    const u8 *mac, union vxlan_addr *ip,
 			    __u16 state, __u16 flags,
 			    __be16 port, __be32 src_vni, __be32 vni,
@@ -687,37 +740,17 @@ static int vxlan_fdb_create(struct vxlan_dev *vxlan,
 		if (!(flags & NLM_F_CREATE))
 			return -ENOENT;
 
-		if (vxlan->cfg.addrmax &&
-		    vxlan->addrcnt >= vxlan->cfg.addrmax)
-			return -ENOSPC;
-
 		/* Disallow replace to add a multicast entry */
 		if ((flags & NLM_F_REPLACE) &&
 		    (is_multicast_ether_addr(mac) || is_zero_ether_addr(mac)))
 			return -EOPNOTSUPP;
 
 		netdev_dbg(vxlan->dev, "add %pM -> %pIS\n", mac, ip);
-		f = kmalloc(sizeof(*f), GFP_ATOMIC);
-		if (!f)
-			return -ENOMEM;
-
-		notify = 1;
-		f->state = state;
-		f->flags = ndm_flags;
-		f->updated = f->used = jiffies;
-		f->vni = src_vni;
-		INIT_LIST_HEAD(&f->remotes);
-		memcpy(f->eth_addr, mac, ETH_ALEN);
-
-		rc = vxlan_fdb_append(f, ip, port, vni, ifindex, &rd);
-		if (rc < 0) {
-			kfree(f);
+		rc = vxlan_fdb_create(vxlan, mac, ip, state, port, src_vni,
+				      vni, ifindex, ndm_flags, &f);
+		if (rc < 0)
 			return rc;
-		}
-
-		++vxlan->addrcnt;
-		hlist_add_head_rcu(&f->hlist,
-				   vxlan_fdb_head(vxlan, mac, src_vni));
+		notify = 1;
 	}
 
 	if (notify) {
@@ -863,7 +896,7 @@ static int vxlan_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
 		return -EAFNOSUPPORT;
 
 	spin_lock_bh(&vxlan->hash_lock);
-	err = vxlan_fdb_create(vxlan, addr, &ip, ndm->ndm_state, flags,
+	err = vxlan_fdb_update(vxlan, addr, &ip, ndm->ndm_state, flags,
 			       port, src_vni, vni, ifindex, ndm->ndm_flags);
 	spin_unlock_bh(&vxlan->hash_lock);
 
@@ -1006,7 +1039,7 @@ static bool vxlan_snoop(struct net_device *dev,
 
 		/* close off race between vxlan_flush and incoming packets */
 		if (netif_running(dev))
-			vxlan_fdb_create(vxlan, src_mac, src_ip,
+			vxlan_fdb_update(vxlan, src_mac, src_ip,
 					 NUD_REACHABLE,
 					 NLM_F_EXCL|NLM_F_CREATE,
 					 vxlan->cfg.dst_port,
@@ -3170,7 +3203,7 @@ static int __vxlan_dev_create(struct net *net, struct net_device *dev,
 
 	/* create an fdb entry for a valid default destination */
 	if (!vxlan_addr_any(&vxlan->default_dst.remote_ip)) {
-		err = vxlan_fdb_create(vxlan, all_zeros_mac,
+		err = vxlan_fdb_update(vxlan, all_zeros_mac,
 				       &vxlan->default_dst.remote_ip,
 				       NUD_REACHABLE | NUD_PERMANENT,
 				       NLM_F_EXCL | NLM_F_CREATE,
@@ -3450,7 +3483,7 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[],
 					   old_dst.remote_ifindex, 0);
 
 		if (!vxlan_addr_any(&dst->remote_ip)) {
-			err = vxlan_fdb_create(vxlan, all_zeros_mac,
+			err = vxlan_fdb_update(vxlan, all_zeros_mac,
 					       &dst->remote_ip,
 					       NUD_REACHABLE | NUD_PERMANENT,
 					       NLM_F_CREATE | NLM_F_APPEND,