net: hns3: MAC table entry count function increases operation 0 value protection measures

When updating the available MAC VLAN table counts,
MAC VLAN table entry count function adds
operation 0 value protection measures.
Signed-off-by: liuzhongzhu <liuzhongzhu@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c

@@ -5830,9 +5830,12 @@ static void hclge_update_umv_space(struct hclge_vport *vport, bool is_free)
 	if (is_free) {
 		if (vport->used_umv_num > hdev->priv_umv_size)
 			hdev->share_umv_size++;
-		vport->used_umv_num--;
+
+		if (vport->used_umv_num > 0)
+			vport->used_umv_num--;
 	} else {
-		if (vport->used_umv_num >= hdev->priv_umv_size)
+		if (vport->used_umv_num >= hdev->priv_umv_size &&
+		    hdev->share_umv_size > 0)
 			hdev->share_umv_size--;
 		vport->used_umv_num++;
 	}