Kernel: Implement basic RWLock

kernel/include/kernel/Lock/RWLock.h

@@ -0,0 +1,97 @@
+#pragma once
+
+#include <kernel/Lock/Mutex.h>
+#include <kernel/Lock/LockGuard.h>
+
+namespace Kernel
+{
+
+	class RWLock
+	{
+		BAN_NON_COPYABLE(RWLock);
+		BAN_NON_MOVABLE(RWLock);
+	public:
+		RWLock() = default;
+
+		void rd_lock()
+		{
+			LockGuard _(m_mutex);
+			while (m_writers_waiting > 0 || m_writer_active)
+				m_thread_blocker.block_indefinite(&m_mutex);
+			m_readers_active++;
+		}
+
+		void rd_unlock()
+		{
+			LockGuard _(m_mutex);
+			if (--m_readers_active == 0)
+				m_thread_blocker.unblock();
+		}
+
+		void wr_lock()
+		{
+			LockGuard _(m_mutex);
+			m_writers_waiting++;
+			while (m_readers_active > 0 || m_writer_active)
+				m_thread_blocker.block_indefinite(&m_mutex);
+			m_writers_waiting--;
+			m_writer_active = true;
+		}
+
+
+		void wr_unlock()
+		{
+			LockGuard _(m_mutex);
+			m_writer_active = false;
+			m_thread_blocker.unblock();
+		}
+
+	private:
+		Mutex m_mutex;
+		ThreadBlocker m_thread_blocker;
+		uint32_t m_readers_active  { 0 };
+		uint32_t m_writers_waiting { 0 };
+		bool m_writer_active { false };
+	};
+
+	class RWLockRDGuard
+	{
+		BAN_NON_COPYABLE(RWLockRDGuard);
+		BAN_NON_MOVABLE(RWLockRDGuard);
+	public:
+		RWLockRDGuard(RWLock& lock)
+			: m_lock(lock)
+		{
+			m_lock.rd_lock();
+		}
+
+		~RWLockRDGuard()
+		{
+			m_lock.rd_unlock();
+		}
+
+	private:
+		RWLock& m_lock;
+	};
+
+	class RWLockWRGuard
+	{
+		BAN_NON_COPYABLE(RWLockWRGuard);
+		BAN_NON_MOVABLE(RWLockWRGuard);
+	public:
+		RWLockWRGuard(RWLock& lock)
+			: m_lock(lock)
+		{
+			m_lock.wr_lock();
+		}
+
+		~RWLockWRGuard()
+		{
+			m_lock.wr_unlock();
+		}
+
+	private:
+		RWLock& m_lock;
+	};
+
+}