splice_file_range
ret = splice_file_range(src_file, &src_off, dst_file, &dst_off,
bytes = splice_file_range(src_file, &src_off, dst_file,
EXPORT_SYMBOL(splice_file_range);
ssize_t splice_file_range(struct file *in, loff_t *ppos, struct file *out,
return splice_file_range(in, &pos_in, out, &pos_out, len);