Refactor to separate out the functions of starting and stopping threads
so that they can be used in other helpers.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Tested-and-reviewed-by: NKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>