Function do_vn_io_fault

freebsd/kern/vfs_vnops.c:153–161

* Returns true if vn_io_fault mode of handling the i/o request should * be used. */

 * be used.
 */
static bool
do_vn_io_fault(struct vnode *vp, struct uio *uio)
{
	struct mount *mp;

	return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG &&
	    (mp = vp->v_mount) != NULL &&
	    (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable);
}

/*
 * Structure used to pass arguments to vn_io_fault1(), to do either