44     spin_rw_mutex() noexcept : m_state(0) {  in spin_rw_mutex()
50         __TBB_ASSERT(!m_state, "destruction of an acquired mutex");  in ~spin_rw_mutex()
68             state_type s = m_state.load(std::memory_order_relaxed);  in lock()
70                 if (m_state.compare_exchange_strong(s, WRITER))  in lock()
74                 m_state |= WRITER_PENDING;  in lock()
84         state_type s = m_state.load(std::memory_order_relaxed);  in try_lock()
86             if (m_state.compare_exchange_strong(s, WRITER)) {  in try_lock()
97         m_state &= READERS;  in unlock()
104             state_type s = m_state.load(std::memory_order_relaxed);  in lock_shared()
106                 state_type prev_state = m_state.fetch_add(ONE_READER);  in lock_shared()
111                 m_state -= ONE_READER;  in lock_shared()
115         __TBB_ASSERT(m_state & READERS, "invalid state of a read lock: no readers");  in lock_shared()
121         state_type s = m_state.load(std::memory_order_relaxed);  in try_lock_shared()
123             state_type prev_state = m_state.fetch_add(ONE_READER);  in try_lock_shared()
129             m_state -= ONE_READER;  in try_lock_shared()
136         __TBB_ASSERT(m_state & READERS, "invalid state of a read lock: no readers");  in unlock_shared()
138         m_state -= ONE_READER;  in unlock_shared()
148         state_type s = m_state.load(std::memory_order_relaxed);  in upgrade()
154             if (m_state.compare_exchange_strong(s, s | WRITER | WRITER_PENDING)) {  in upgrade()
156 …         while ((m_state.load(std::memory_order_relaxed) & READERS) != ONE_READER) backoff.pause();  in upgrade()
157 …__TBB_ASSERT((m_state & (WRITER_PENDING|WRITER)) == (WRITER_PENDING | WRITER), "invalid state when…  in upgrade()
159                 m_state -= (ONE_READER + WRITER_PENDING);  in upgrade()
172         m_state += (ONE_READER - WRITER);  in downgrade()
173         __TBB_ASSERT(m_state & READERS, "invalid state after downgrade: no readers");  in downgrade()
187     std::atomic<state_type> m_state;  variable