diff --git a/sys/contrib/openzfs/include/os/freebsd/linux/compiler.h b/sys/contrib/openzfs/include/os/freebsd/linux/compiler.h
--- a/sys/contrib/openzfs/include/os/freebsd/linux/compiler.h
+++ b/sys/contrib/openzfs/include/os/freebsd/linux/compiler.h
@@ -1,101 +1,40 @@
 /*
- * Copyright (c) 2010 Isilon Systems, Inc.
- * Copyright (c) 2010 iXsystems, Inc.
- * Copyright (c) 2010 Panasas, Inc.
- * Copyright (c) 2013-2016 Mellanox Technologies, Ltd.
- * Copyright (c) 2015 François Tigeot
- * All rights reserved.
+ * Copyright (c) 2024 Warner Losh.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice unmodified, this list of conditions, and the following
- *    disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
- * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
- * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * $FreeBSD$
+ * Various compatibility macros that ZFS needs for FreeBSD to provide that Linux
+ * already provides, or that are in the Linux os library compat stuff.
  */
-#ifndef	_LINUX_COMPILER_H_
-#define	_LINUX_COMPILER_H_
+#pragma once
 
 #include <sys/cdefs.h>
 
-#define	__user
-#define	__kernel
-#define	__safe
-#define	__force
-#define	__nocast
-#define	__iomem
-#define	__chk_user_ptr(x)		((void)0)
-#define	__chk_io_ptr(x)			((void)0)
-#define	__builtin_warning(x, y...)	(1)
-#define	__acquires(x)
-#define	__releases(x)
-#define	__acquire(x)			do { } while (0)
-#define	__release(x)			do { } while (0)
-#define	__cond_lock(x, c)		(c)
-#define	__bitwise
-#define	__devinitdata
-#define	__deprecated
-#define	__init
-#define	__initconst
-#define	__devinit
-#define	__devexit
-#define	__exit
-#define	__rcu
-#define	__percpu
-#define	__weak __weak_symbol
-#define	__malloc
-#define	___stringify(...)		#__VA_ARGS__
-#define	__stringify(...)		___stringify(__VA_ARGS__)
-#define	__attribute_const__		__attribute__((__const__))
-#undef __always_inline
-#define	__always_inline			inline
-#define	noinline			__noinline
-#define	____cacheline_aligned		__aligned(CACHE_LINE_SIZE)
+#include <compat/linuxkpi/common/include/linux/compiler.h>
+
 #define	zfs_fallthrough			__attribute__((__fallthrough__))
 
-#if !defined(_KERNEL) && !defined(_STANDALONE)
-#define	likely(x)			__builtin_expect(!!(x), 1)
-#define	unlikely(x)			__builtin_expect(!!(x), 0)
+/*
+ * Older LinuxKPI code where some or all of these aren't defined. Provide them
+ * all here.
+ */
+#ifndef ACCESS_ONCE
+#define	ACCESS_ONCE(x)			(*(volatile __typeof(x) *)(uintptr_t)&(x))
 #endif
-#define	typeof(x)			__typeof(x)
-
-#define	uninitialized_var(x)		x = x
-#define	__maybe_unused			__unused
-#define	__always_unused			__unused
-#define	__must_check			__result_use_check
-
-#define	__printf(a, b)			__printflike(a, b)
 
-#define	barrier()			__asm__ __volatile__("": : :"memory")
-#define	___PASTE(a, b) a##b
-#define	__PASTE(a, b) ___PASTE(a, b)
-
-#define	ACCESS_ONCE(x)			(*(volatile __typeof(x) *)&(x))
-
-#define	WRITE_ONCE(x, v) do {		\
+#ifndef WRITE_ONCE
+#define	WRITE_ONCE(x,v) do {		\
 	barrier();			\
 	ACCESS_ONCE(x) = (v);		\
 	barrier();			\
 } while (0)
+#endif
 
-#define	lockless_dereference(p) READ_ONCE(p)
-
-#define	_AT(T, X)	((T)(X))
-
-#endif	/* _LINUX_COMPILER_H_ */
+#ifndef READ_ONCE
+#define	READ_ONCE(x) ({			\
+	__typeof(x) __var = ({		\
+		barrier();		\
+		ACCESS_ONCE(x);		\
+	});				\
+	barrier();			\
+	__var;				\
+})
+#endif
diff --git a/sys/contrib/openzfs/include/os/freebsd/spl/sys/ccompat.h b/sys/contrib/openzfs/include/os/freebsd/spl/sys/ccompat.h
--- a/sys/contrib/openzfs/include/os/freebsd/spl/sys/ccompat.h
+++ b/sys/contrib/openzfs/include/os/freebsd/spl/sys/ccompat.h
@@ -112,15 +112,6 @@
 		n->next->pprev = n->pprev;
 }
 	/* BEGIN CSTYLED */
-#define	READ_ONCE(x) ({			\
-	__typeof(x) __var = ({		\
-		barrier();		\
-		ACCESS_ONCE(x);		\
-	});				\
-	barrier();			\
-	__var;				\
-})
-
 #define	HLIST_HEAD_INIT { }
 #define	HLIST_HEAD(name) struct hlist_head name = HLIST_HEAD_INIT
 #define	INIT_HLIST_HEAD(head) (head)->first = NULL
diff --git a/sys/contrib/openzfs/include/os/freebsd/spl/sys/debug.h b/sys/contrib/openzfs/include/os/freebsd/spl/sys/debug.h
--- a/sys/contrib/openzfs/include/os/freebsd/spl/sys/debug.h
+++ b/sys/contrib/openzfs/include/os/freebsd/spl/sys/debug.h
@@ -95,10 +95,6 @@
 #ifndef expect
 #define	expect(expr, value) (__builtin_expect((expr), (value)))
 #endif
-#ifndef __linux__
-#define	likely(expr)   expect((expr) != 0, 1)
-#define	unlikely(expr) expect((expr) != 0, 0)
-#endif
 
 #define	PANIC(fmt, a...)						\
 	spl_panic(__FILE__, __FUNCTION__, __LINE__, fmt, ## a)