title: What's the difference between sysfs_create_file() and sysfs_create_group()?
body: <p>The two functions' prototypes:</p>
  
  <pre><code>int sysfs_create_group(struct kobject *kobj, const struct attribute_group *grp)
  int sysfs_create_file(struct kobject * kobj, const struct attribute * attr)
  </code></pre>
  
  <p>It seems to me that these two functions will both create attributes under the <code>kobj-&gt;name</code> directory in <code>sysfs</code>. The only difference I can find is, the group func can create a group of attributes in one time as the file func only one attribute.
  So are there other deferences？ Or is my understanding of the functions wrong?</p>