vxlan: Avoid unnecessary updates to FDB 'used' time

Now that the VXLAN driver ages out FDB entries based on their 'updated'
time we can remove unnecessary updates of the 'used' time from the Rx
path and the control path, so that the 'used' time is only updated by
the Tx path.

Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20250204145549.1216254-8-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/vxlan/vxlan_core.c

@@ -1049,10 +1049,8 @@ static int vxlan_fdb_update_existing(struct vxlan_dev *vxlan,
 		notify |= rc;
 	}
 
-	if (ndm_flags & NTF_USE) {
-		WRITE_ONCE(f->used, jiffies);
+	if (ndm_flags & NTF_USE)
 		WRITE_ONCE(f->updated, jiffies);
-	}
 
 	if (notify) {
 		if (rd == NULL)
@@ -1297,7 +1295,7 @@ int __vxlan_fdb_delete(struct vxlan_dev *vxlan,
 	struct vxlan_fdb *f;
 	int err = -ENOENT;
 
-	f = vxlan_find_mac(vxlan, addr, src_vni);
+	f = __vxlan_find_mac(vxlan, addr, src_vni);
 	if (!f)
 		return err;
 
@@ -1464,7 +1462,7 @@ static enum skb_drop_reason vxlan_snoop(struct net_device *dev,
 		ifindex = src_ifindex;
 #endif
 
-	f = vxlan_find_mac(vxlan, src_mac, vni);
+	f = __vxlan_find_mac(vxlan, src_mac, vni);
 	if (likely(f)) {
 		struct vxlan_rdst *rdst = first_remote_rcu(f);
 		unsigned long now = jiffies;
@@ -4773,7 +4771,7 @@ vxlan_fdb_offloaded_set(struct net_device *dev,
 
 	spin_lock_bh(&vxlan->hash_lock[hash_index]);
 
-	f = vxlan_find_mac(vxlan, fdb_info->eth_addr, fdb_info->vni);
+	f = __vxlan_find_mac(vxlan, fdb_info->eth_addr, fdb_info->vni);
 	if (!f)
 		goto out;
 
@@ -4829,7 +4827,7 @@ vxlan_fdb_external_learn_del(struct net_device *dev,
 	hash_index = fdb_head_index(vxlan, fdb_info->eth_addr, fdb_info->vni);
 	spin_lock_bh(&vxlan->hash_lock[hash_index]);
 
-	f = vxlan_find_mac(vxlan, fdb_info->eth_addr, fdb_info->vni);
+	f = __vxlan_find_mac(vxlan, fdb_info->eth_addr, fdb_info->vni);
 	if (!f)
 		err = -ENOENT;
 	else if (f->flags & NTF_EXT_LEARNED)