do_splice_direct
bytes = do_splice_direct(old_file, &old_pos,
retval = do_splice_direct(fd_file(in), &pos, fd_file(out), &out_pos,
ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out, len, 0);
ret = do_splice_direct(src_fp->filp, &src_off,
EXPORT_SYMBOL(do_splice_direct);
ssize_t do_splice_direct(struct file *in, loff_t *ppos, struct file *out,