md: md_unregister_thread should cope with being passed NULL
Mostly md_unregister_thread is only called when we know that the
thread is NULL, but sometimes we need to check first. It is safer
to put the check inside md_unregister_thread itself.
Signed-off-by: NNeilBrown <neilb@suse.de>
Showing
想要评论请 注册 或 登录