bio_associate_blkcg — associate a bio with the specified blkcg
| int bio_associate_blkcg ( | struct bio * bio, | 
| struct cgroup_subsys_state * blkcg_css ); | 
   Associate bio with the blkcg specified by blkcg_css.  Block layer will
   treat bio as if it were issued by a task which belongs to the blkcg.
   
   This function takes an extra reference of blkcg_css which will be put
   when bio is released.  The caller must own bio and is responsible for
   synchronizing calls to this function.