Kernel: Fix most of mutex + block race conditions

All block functions now take an optional mutex parameter that is
atomically unlocked instead of having the user unlock it before hand.
This prevents a ton of race conditions everywhere in the code!

kernel/kernel/Memory/MemoryBackedRegion.cpp

@@ -1,4 +1,3 @@
-#include <kernel/Lock/LockGuard.h>
 #include <kernel/Memory/Heap.h>
 #include <kernel/Memory/MemoryBackedRegion.h>
 

kernel/kernel/Memory/MemoryRegion.cpp

@@ -1,3 +1,4 @@
+#include <kernel/Lock/LockGuard.h>
 #include <kernel/Memory/MemoryRegion.h>
 
 namespace Kernel
@@ -59,4 +60,24 @@ namespace Kernel
 		return ret;
 	}
 
+	void MemoryRegion::pin()
+	{
+		LockGuard _(m_pinned_mutex);
+		m_pinned_count++;
+	}
+
+	void MemoryRegion::unpin()
+	{
+		LockGuard _(m_pinned_mutex);
+		if (--m_pinned_count == 0)
+			m_pinned_blocker.unblock();
+	}
+
+	void MemoryRegion::wait_not_pinned()
+	{
+		LockGuard _(m_pinned_mutex);
+		while (m_pinned_count)
+			m_pinned_blocker.block_with_timeout_ms(100, &m_pinned_mutex);
+	}
+
 }

kernel/kernel/Memory/VirtualRange.cpp

@@ -1,4 +1,3 @@
-#include <kernel/Lock/LockGuard.h>
 #include <kernel/Memory/Heap.h>
 #include <kernel/Memory/VirtualRange.h>