rt_mutex_cmpxchg_acquire
if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
return rt_mutex_cmpxchg_acquire(lock, NULL, current);
if (unlikely(!rt_mutex_cmpxchg_acquire(&lock->lock, NULL, current)))
if (unlikely(!rt_mutex_cmpxchg_acquire(rtm, NULL, current)))
if (likely(rt_mutex_cmpxchg_acquire(rtm, current, NULL)))
if (likely(rt_mutex_cmpxchg_acquire(rtm, NULL, current)))
if (unlikely(!rt_mutex_cmpxchg_acquire(rtm, NULL, current)))