Index: sys/compat/freebsd32/freebsd32_ioctl.h
===================================================================
--- sys/compat/freebsd32/freebsd32_ioctl.h
+++ sys/compat/freebsd32/freebsd32_ioctl.h
@@ -38,11 +38,6 @@
 
 typedef __uint32_t caddr_t32;
 
-struct fiodgname_arg32 {
-	int		len;
-	caddr_t32	buf;
-};
-
 struct mem_range_op32
 {
 	caddr_t32	mo_desc;
@@ -60,7 +55,6 @@
 	int		pbm_memattr;
 };
 
-#define	FIODGNAME_32	_IOW('f', 120, struct fiodgname_arg32)
 #define	MEMRANGE_GET32	_IOWR('m', 50, struct mem_range_op32)
 #define	MEMRANGE_SET32	_IOW('m', 51, struct mem_range_op32)
 #define	SG_IO_32	_IOWR(SGIOC, 0x85, struct sg_io_hdr32)
Index: sys/compat/freebsd32/freebsd32_ioctl.c
===================================================================
--- sys/compat/freebsd32/freebsd32_ioctl.c
+++ sys/compat/freebsd32/freebsd32_ioctl.c
@@ -58,22 +58,6 @@
 
 CTASSERT(sizeof(struct mem_range_op32) == 12);
 
-static int
-freebsd32_ioctl_fiodgname(struct thread *td,
-    struct freebsd32_ioctl_args *uap, struct file *fp)
-{
-	struct fiodgname_arg fgn;
-	struct fiodgname_arg32 fgn32;
-	int error;
-
-	if ((error = copyin(uap->data, &fgn32, sizeof fgn32)) != 0)
-		return (error);
-	CP(fgn32, fgn, len);
-	PTRIN_CP(fgn32, fgn, buf);
-	error = fo_ioctl(fp, FIODGNAME, (caddr_t)&fgn, td->td_ucred, td);
-	return (error);
-}
-
 static int
 freebsd32_ioctl_memrange(struct thread *td,
     struct freebsd32_ioctl_args *uap, struct file *fp)
@@ -237,10 +221,6 @@
 	}
 
 	switch (uap->com) {
-	case FIODGNAME_32:
-		error = freebsd32_ioctl_fiodgname(td, uap, fp);
-		break;
-
 	case MEMRANGE_GET32:	/* FALLTHROUGH */
 	case MEMRANGE_SET32:
 		error = freebsd32_ioctl_memrange(td, uap, fp);
Index: sys/fs/devfs/devfs_vnops.c
===================================================================
--- sys/fs/devfs/devfs_vnops.c
+++ sys/fs/devfs/devfs_vnops.c
@@ -79,6 +79,14 @@
 #include <vm/vm_extern.h>
 #include <vm/vm_object.h>
 
+#ifdef COMPAT_FREEBSD32
+struct fiodgname_arg32 {
+	int		len;
+	uint32_t	buf;	/* (void *) */
+};
+#define FIODGNAME_32	_IOC_NEWTYPE(FIODGNAME, struct fiodgname_arg32)
+#endif
+
 static MALLOC_DEFINE(M_CDEVPDATA, "DEVFSP", "Metainfo for cdev-fp data");
 
 struct mtx	devfs_de_interlock;
@@ -767,6 +775,29 @@
 	return (error);
 }
 
+static void *
+fiodgname_buf_get_ptr(void *fgnp, u_long com)
+{
+	union {
+		struct fiodgname_arg	fgn;
+#ifdef COMPAT_FREEBSD32
+		struct fiodgname_arg32	fgn32;
+#endif
+	} *fgnup;
+
+	fgnup = fgnp;
+	switch (com) {
+	case FIODGNAME:
+		return (fgnup->fgn.buf);
+#ifdef COMPAT_FREEBSD32
+	case FIODGNAME_32:
+		return ((void *)(uintptr_t)fgnup->fgn32.buf);
+#endif
+	default:
+		panic("Unhandled ioctl command %ld", com);
+	}
+}
+
 static int
 devfs_ioctl(struct vop_ioctl_args *ap)
 {
@@ -789,24 +820,27 @@
 	KASSERT(dev->si_refcount > 0,
 	    ("devfs: un-referenced struct cdev *(%s)", devtoname(dev)));
 
-	if (com == FIODTYPE) {
+	switch (com) {
+	case FIODTYPE:
 		*(int *)ap->a_data = dsw->d_flags & D_TYPEMASK;
 		error = 0;
-		goto out;
-	} else if (com == FIODGNAME) {
+		break;
+	case FIODGNAME:
+#ifdef	COMPAT_FREEBSD32
+	case FIODGNAME_32:
+#endif
 		fgn = ap->a_data;
 		p = devtoname(dev);
 		i = strlen(p) + 1;
 		if (i > fgn->len)
 			error = EINVAL;
 		else
-			error = copyout(p, fgn->buf, i);
-		goto out;
+			error = copyout(p, fiodgname_buf_get_ptr(fgn, com), i);
+		break;
+	default:
+		error = dsw->d_ioctl(dev, com, ap->a_data, ap->a_fflag, td);
 	}
 
-	error = dsw->d_ioctl(dev, com, ap->a_data, ap->a_fflag, td);
-
-out:
 	dev_relthread(dev, ref);
 	if (error == ENOIOCTL)
 		error = ENOTTY;