vn_ioctl         1440 kern/vfs_syscalls.c 		error = vn_ioctl(fp, DIOCGPART, (void *)&dpart, p);
vn_ioctl           66 kern/vfs_vnops.c 	{ vn_read, vn_write, vn_ioctl, vn_poll, vn_kqfilter, vn_statfile,
vn_ioctl          440 sys/vnode.h    int	vn_ioctl(struct file *, u_long, caddr_t, struct proc *);