vxlan: Unsplit default FDB entry creation and notification

Commit 0241b836732f ("vxlan: fix default fdb entry netlink notify
ordering during netdev create") split the creation of the default FDB
entry from its notification to avoid sending a RTM_NEWNEIGH notification
before RTM_NEWLINK.

Previous patches restructured the code so that the default FDB entry is
created after registering the VXLAN device and the notification about
the new entry immediately follows its creation.

Therefore, simplify the code and revert back to vxlan_fdb_update() which
takes care of both creating the FDB entry and notifying user space
about it.

Hold the FDB hash lock when calling vxlan_fdb_update() like it expects.
A subsequent patch will add a lockdep assertion to make sure this is
indeed the case.

Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20250415121143.345227-5-idosch@nvidia.com
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 8 insertions, 13 deletions

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 915ce73f0c87..d3dfc4af9556 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -3943,7 +3943,6 @@ static int __vxlan_dev_create(struct net *net, struct net_device *dev,
 	struct vxlan_net *vn = net_generic(net, vxlan_net_id);
 	struct vxlan_dev *vxlan = netdev_priv(dev);
 	struct net_device *remote_dev = NULL;
-	struct vxlan_fdb *f = NULL;
 	struct vxlan_rdst *dst;
 	int err;
 
@@ -3976,33 +3975,29 @@ 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(&dst->remote_ip)) {
-		err = vxlan_fdb_create(vxlan, all_zeros_mac,
+		u32 hash_index = fdb_head_index(vxlan, all_zeros_mac,
+						dst->remote_vni);
+
+		spin_lock_bh(&vxlan->hash_lock[hash_index]);
+		err = vxlan_fdb_update(vxlan, all_zeros_mac,
 				       &dst->remote_ip,
 				       NUD_REACHABLE | NUD_PERMANENT,
+				       NLM_F_EXCL | NLM_F_CREATE,
 				       vxlan->cfg.dst_port,
 				       dst->remote_vni,
 				       dst->remote_vni,
 				       dst->remote_ifindex,
-				       NTF_SELF, 0, &f, extack);
+				       NTF_SELF, 0, true, extack);
+		spin_unlock_bh(&vxlan->hash_lock[hash_index]);
 		if (err)
 			goto unlink;
 	}
 
-	if (f) {
-		/* notify default fdb entry */
-		err = vxlan_fdb_notify(vxlan, f, first_remote_rtnl(f),
-				       RTM_NEWNEIGH, true, extack);
-		if (err)
-			goto fdb_destroy;
-	}
-
 	list_add(&vxlan->next, &vn->vxlan_list);
 	if (remote_dev)
 		dst->remote_dev = remote_dev;
 	return 0;
 
-fdb_destroy:
-	vxlan_fdb_destroy(vxlan, f, false, false);
 unlink:
 	if (remote_dev)
 		netdev_upper_dev_unlink(remote_dev, dev);