diff --git a/drivers/gpu/nvgpu/include/nvgpu/barrier.h b/drivers/gpu/nvgpu/include/nvgpu/barrier.h
index bd0d820e6..8387a97dc 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/barrier.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/barrier.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2020, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2017-2021, NVIDIA CORPORATION.  All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -44,8 +44,30 @@
 #define nvgpu_smp_rmb()	nvgpu_smp_rmb_impl()
 #define nvgpu_smp_wmb()	nvgpu_smp_wmb_impl()
 
-#define NV_READ_ONCE(x)		NV_READ_ONCE_IMPL((x))
-#define NV_WRITE_ONCE(x, y)	NV_WRITE_ONCE_IMPL((x), (y))
+/**
+ * @brief Compilers can do optimizations assuming there is a single thread
+ * executing the code. For example, a variable read in a loop from one thread
+ * may not see the update from another thread because compiler has assumed that
+ * it's value cannot change from the one initialized before the loop. There are
+ * other possibilities like multiple references to a variable when the code
+ * assumes that it should see a constant value. In general, this macro should
+ * never be used by nvgpu driver code, and many of the current uses in driver
+ * are likely wrong.
+ * For more info see: URL = lwn.net/Articles/508991/
+ *
+ * @param x [in] variable that needs to turn into a volatile type temporarily.
+ */
+#define NV_READ_ONCE(x)		(*((volatile typeof(x) *)&x))
+
+/**
+ * @brief Ensure ordered writes.
+ *
+ * @param x    Variable to be updated.
+ * @param y    Value to be written.
+ *
+ * Prevent compiler optimizations from mangling writes.
+ */
+#define NV_WRITE_ONCE(x, y)	(*((volatile typeof(x) *)(&(x))) = (y))
 
 /*
  * Sometimes we want to prevent speculation.
diff --git a/drivers/gpu/nvgpu/include/nvgpu/linux/barrier.h b/drivers/gpu/nvgpu/include/nvgpu/linux/barrier.h
index 2864b241d..6c35a1d5c 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/linux/barrier.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/linux/barrier.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2020, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2017-2021, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -27,9 +27,6 @@
 #define nvgpu_smp_rmb_impl()	smp_rmb()
 #define nvgpu_smp_wmb_impl()	smp_wmb()
 
-#define NV_READ_ONCE_IMPL(x)		READ_ONCE(x)
-#define NV_WRITE_ONCE_IMPL(x, y)	WRITE_ONCE(x, y)
-
 #ifdef speculation_barrier
 #define nvgpu_speculation_barrier_impl() speculation_barrier()
 #else
diff --git a/drivers/gpu/nvgpu/include/nvgpu/posix/barrier.h b/drivers/gpu/nvgpu/include/nvgpu/posix/barrier.h
index 3f5c8c658..00743d229 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/posix/barrier.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/posix/barrier.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2020, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2017-2021, NVIDIA CORPORATION.  All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -25,8 +25,6 @@
 
 #include <nvgpu/posix/utils.h>
 
-#define READ_ONCE(x)	(*(volatile __typeof__(x) *)&x)
-
 /*
  * TODO: implement all these!
  */
@@ -38,7 +36,4 @@
 #define nvgpu_smp_rmb_impl()
 #define nvgpu_smp_wmb_impl()
 
-#define NV_READ_ONCE_IMPL(x)		READ_ONCE(x)
-#define NV_WRITE_ONCE_IMPL(x, y)	WRITE_ONCE(x, y)
-
 #endif /* NVGPU_POSIX_BARRIER_H */
diff --git a/drivers/gpu/nvgpu/include/nvgpu/posix/utils.h b/drivers/gpu/nvgpu/include/nvgpu/posix/utils.h
index c6a2dab52..6030d1718 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/posix/utils.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/posix/utils.h
@@ -496,22 +496,6 @@ static inline unsigned int nvgpu_posix_hweight64(uint64_t x)
 /** Defined to match kernel macro names. */
 #define likely(x)	(x)
 
-/*
- * Prevent compiler optimizations from mangling writes. But likely most uses of
- * this in nvgpu are incorrect (i.e unnecessary).
- */
-/**
- * @brief Ensure ordered writes.
- *
- * @param p	Variable to be updated.
- * @param v	Value to be written.
- */
-#define WRITE_ONCE(p, v)				\
-	({						\
-		volatile typeof(p) *__p__ = &(p);	\
-		*__p__ = (v);				\
-	})
-
 /**
  * @brief Get the container which holds the member.
  *
diff --git a/userspace/units/posix/utils/posix-utils.c b/userspace/units/posix/utils/posix-utils.c
index 39ef0205c..785e38c76 100644
--- a/userspace/units/posix/utils/posix-utils.c
+++ b/userspace/units/posix/utils/posix-utils.c
@@ -27,6 +27,7 @@
 #include <unit/unit.h>
 
 #include <nvgpu/utils.h>
+#include <nvgpu/barrier.h>
 
 #include "posix-utils.h"
 
@@ -487,10 +488,10 @@ int test_write_once(struct unit_module *m,
 	test1 = 20;
 	for (i = 0 ; i < 10; i++) {
 		test1 += 1;
-		WRITE_ONCE(result, test1);
+		NV_WRITE_ONCE(result, test1);
 		if (result != test1) {
 			unit_return_fail(m,
-				"WRITE_ONCE failure %d\n", result);
+				"NV_WRITE_ONCE failure %d\n", result);
 		}
 	}