91   // The leaf mutexes can be locked under any other non-leaf mutex,
92   // but no other mutex can be locked while under a leaf mutex.
94   // Multiple mutexes of this type can be locked at the same time.
110   // The table fixes what mutexes can be locked under what mutexes.
112   // then Bar mutex can be locked while under Foo mutex.
172       bool locked = (state & (kWriterLock | kReaderLockMask)) != 0;  in Lock()  local
173       if (LIKELY(!locked)) {  in Lock()
174         // The mutex is not read-/write-locked, try to lock.  in Lock()
192       if (LIKELY(!locked))  in Lock()
193         return;  // We've locked the mutex.  in Lock()
216       // The mutex is not read-/write-locked, try to lock.  in TryLock()
258       bool locked = (state & kWriterLock) != 0;  in ReadLock()  local
260       if (LIKELY(!locked)) {  in ReadLock()
276       if (LIKELY(!locked))  in ReadLock()
277         return;  // We've locked the mutex.  in ReadLock()
313   // owns the mutex but a child checks that it is locked. Rather than
333   //    if non zero, the mutex is read-locked
335   //    if not zero, the mutex is write-locked
337   //    if non zero, the mutex is read- or write-locked
340   //    if set, the mutex is write-locked