title: Implicit declaration of function error
body: <p>While compiling code for softiwarp using this <a href="http://www.reflectionsofthevoid.com/2011/03/how-to-install-soft-iwarp-on-ubuntu.html" rel="nofollow">guide</a> 
  I encountered the following errors while compile codes in kernel directory.</p>
  
  <pre><code>error: implicit declaration of function ‘remap_vmalloc_range’
  error: implicit declaration of function ‘vmalloc’
  error: implicit declaration of function ‘vmalloc_user’ 
  error: implicit declaration of function ‘vfree’
  </code></pre>
  
  <p>Anyone here could help guide me, how to install the libraries related to this function? I'm using ubuntu 16.04.</p>