genfs_do_io
error = genfs_do_io(vp, off, kva, len, flags, UIO_WRITE,
error = genfs_do_io(vp, off, kva, len, flags, UIO_WRITE,
error = genfs_do_io(vp, off, kva + koff, len, PGO_SYNCIO, rw,
static int genfs_do_io(struct vnode *, off_t, vaddr_t, size_t, int, enum uio_rw,