title: unknown field 'ioctl' specified in initializer
body: <p>I implement a simple example to study the usage of <code>ioctl</code> interface according to the book <em>LDD3</em>. When I compiling the codes, <code>unknown field 'ioctl' specified in initializer.</code> is reported. </p>
  
  <p>I guess the difference of kernel version between <em>LDD3</em>'s and mine causes this error. I'm now using Debian 8 with kernel 3.18.14, which is much newer than the version 2.6 in <em>LDD3</em>.</p>
  
  <p>I don't know how <code>ioctl</code>, or even <code>struct file_operations</code>, changed form 2.6 to 3.18, so please show me some reading materials to clarify it. Of course, besides the reading material, I actually need one solution to fix this problem.</p>