int mlx4_register_vlan(struct mlx4_dev *dev, u8 port, u16 vlan, int *index)
{
	struct mlx4_vlan_table *table = &mlx4_priv(dev)->port[port].vlan_table;
	int i, err = 0;
	int free = -1;

	mutex_lock(&table->mutex);
	for (i = MLX4_VLAN_REGULAR; i < MLX4_MAX_VLAN_NUM; i++) {
		if (free < 0 && (table->refs[i] == 0)) {
			free = i;
			continue;
		}

		if (table->refs[i] &&
		    (vlan == (MLX4_VLAN_MASK &
			      be32_to_cpu(table->entries[i])))) {
			/* Vlan already registered, increase refernce count */
			*index = i;
			++table->refs[i];
			goto out;
 		}
 	}
 
 	if (table->total == table->max) {
 		/* No free vlan entries */
 		err = -ENOSPC;
		goto out;
	}

	/* Register new MAC */
	table->refs[free] = 1;
	table->entries[free] = cpu_to_be32(vlan | MLX4_VLAN_VALID);

	err = mlx4_set_port_vlan_table(dev, port, table->entries);
	if (unlikely(err)) {
		mlx4_warn(dev, "Failed adding vlan: %u\n", vlan);
		table->refs[free] = 0;
		table->entries[free] = 0;
		goto out;
	}

	*index = free;
	++table->total;
out:
	mutex_unlock(&table->mutex);
	return err;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.