ocfs2: no need flush workqueue before destroying it

destroy_workqueue() will do flushing work for us.

Link: http://lkml.kernel.org/r/59E06476.3090502@huawei.com
Signed-off-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Joseph Qi <jiangqi903@gmail.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/dlm/dlmdomain.c

@@ -394,7 +394,6 @@ int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
 static void dlm_destroy_dlm_worker(struct dlm_ctxt *dlm)
 {
 	if (dlm->dlm_worker) {
-		flush_workqueue(dlm->dlm_worker);
 		destroy_workqueue(dlm->dlm_worker);
 		dlm->dlm_worker = NULL;
 	}

fs/ocfs2/dlmfs/dlmfs.c

@@ -670,7 +670,6 @@ static void __exit exit_dlmfs_fs(void)
 {
 	unregister_filesystem(&dlmfs_fs_type);
 
-	flush_workqueue(user_dlm_worker);
 	destroy_workqueue(user_dlm_worker);
 
 	/*

fs/ocfs2/super.c

@@ -2521,10 +2521,8 @@ static void ocfs2_delete_osb(struct ocfs2_super *osb)
 	/* This function assumes that the caller has the main osb resource */
 
 	/* ocfs2_initializer_super have already created this workqueue */
-	if (osb->ocfs2_wq) {
-		flush_workqueue(osb->ocfs2_wq);
+	if (osb->ocfs2_wq)
 		destroy_workqueue(osb->ocfs2_wq);
-	}
 
 	ocfs2_free_slot_info(osb);