title: Linux filp_open error number definitions
body: <p>I have a question about the <code>filp_open</code> function: </p>
  
  <p>I can get the error number from the <code>IS_ERR</code> function but I do not understand the meaning of the error number.</p>
  
  <p>Where can find the <code>filp_open</code> error number definitions?</p>