title: read_proc_t and file_operations in procfs
body: <p>I'm now studying proc file system. I now know that read_proc_t function is called when the proofs file is read, and so for write_proc_t function when the proofs file is written to. But I also find the file_operaitons* field in the definition of proc_dir_entry, and this example code (<a href="http://linux.die.net/lkmpg/x810.html" rel="nofollow">http://linux.die.net/lkmpg/x810.html</a>). </p>
  
  <p>So I'm confused that what would happen if I provide both implementations of read_proc_t function and the read function in file_operations structure? Which has the precedence over the other? Could one be overwritten by the other? Thanks very much.</p>