diff --git a/include/sys/zfs_context.h b/include/sys/zfs_context.h
index dac1e4b69..770cb73f2 100644
--- a/include/sys/zfs_context.h
+++ b/include/sys/zfs_context.h
@@ -203,8 +203,6 @@ extern char *vn_dumpdir;
 #define	CPU_SEQID	((uintptr_t)pthread_self() & (max_ncpus - 1))
 #define	CPU_SEQID_UNSTABLE	CPU_SEQID
 
-#define	ptob(x)		((x) * PAGESIZE)
-
 #define	NN_DIVISOR_1000	(1U << 0)
 #define	NN_NUMBUF_SZ	(6)
 
diff --git a/lib/libspl/include/os/freebsd/sys/param.h b/lib/libspl/include/os/freebsd/sys/param.h
index 55fa1de0e..a69314911 100644
--- a/lib/libspl/include/os/freebsd/sys/param.h
+++ b/lib/libspl/include/os/freebsd/sys/param.h
@@ -58,6 +58,8 @@
 extern size_t spl_pagesize(void);
 #define	PAGESIZE	(spl_pagesize())
 
+#define	ptob(x)		((x) * PAGESIZE)
+
 #ifndef HAVE_EXECVPE
 extern int execvpe(const char *name, char * const argv[], char * const envp[]);
 #endif
diff --git a/lib/libspl/include/os/linux/sys/param.h b/lib/libspl/include/os/linux/sys/param.h
index 814f8feaf..169d5875f 100644
--- a/lib/libspl/include/os/linux/sys/param.h
+++ b/lib/libspl/include/os/linux/sys/param.h
@@ -65,4 +65,6 @@
 extern size_t spl_pagesize(void);
 #define	PAGESIZE	(spl_pagesize())
 
+#define	ptob(x)		((x) * PAGESIZE)
+
 #endif