Index: head/sys/kern/sys_generic.c
===================================================================
--- head/sys/kern/sys_generic.c
+++ head/sys/kern/sys_generic.c
@@ -89,12 +89,14 @@
 #define	SYS_IOCTL_SMALL_SIZE	128	/* bytes */
 #define	SYS_IOCTL_SMALL_ALIGN	8	/* bytes */
 
-int iosize_max_clamp = 0;
+#ifdef __LP64__
+static int iosize_max_clamp = 0;
 SYSCTL_INT(_debug, OID_AUTO, iosize_max_clamp, CTLFLAG_RW,
     &iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX");
-int devfs_iosize_max_clamp = 1;
+static int devfs_iosize_max_clamp = 1;
 SYSCTL_INT(_debug, OID_AUTO, devfs_iosize_max_clamp, CTLFLAG_RW,
     &devfs_iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX for devices");
+#endif
 
 /*
  * Assert that the return value of read(2) and write(2) syscalls fits
@@ -159,6 +161,24 @@
 static uma_zone_t selfd_zone;
 static struct mtx_pool *mtxpool_select;
 
+#ifdef __LP64__
+size_t
+devfs_iosize_max(void)
+{
+
+	return (devfs_iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ?
+	    INT_MAX : SSIZE_MAX);
+}
+
+size_t
+iosize_max(void)
+{
+
+	return (iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ?
+	    INT_MAX : SSIZE_MAX);
+}
+#endif
+
 #ifndef _SYS_SYSPROTO_H_
 struct read_args {
 	int	fd;
Index: head/sys/sys/systm.h
===================================================================
--- head/sys/sys/systm.h
+++ head/sys/sys/systm.h
@@ -148,10 +148,14 @@
 extern const void *zero_region;	/* address space maps to a zeroed page	*/
 
 extern int unmapped_buf_allowed;
-extern int iosize_max_clamp;
-extern int devfs_iosize_max_clamp;
-#define	IOSIZE_MAX	(iosize_max_clamp ? INT_MAX : SSIZE_MAX)
-#define	DEVFS_IOSIZE_MAX	(devfs_iosize_max_clamp ? INT_MAX : SSIZE_MAX)
+
+#ifdef __LP64__
+#define	IOSIZE_MAX		iosize_max()
+#define	DEVFS_IOSIZE_MAX	devfs_iosize_max()
+#else
+#define	IOSIZE_MAX		SSIZE_MAX
+#define	DEVFS_IOSIZE_MAX	SSIZE_MAX
+#endif
 
 /*
  * General function declarations.
@@ -403,6 +407,11 @@
 dev_t dev2udev(struct cdev *x);
 const char *devtoname(struct cdev *cdev);
 
+#ifdef __LP64__
+size_t	devfs_iosize_max(void);
+size_t	iosize_max(void);
+#endif
+
 int poll_no_poll(int events);
 
 /* XXX: Should be void nanodelay(u_int nsec); */