


Q: Given the following code slice:
```
CWE-457___CVE-2024-36882.c___1-55___7.c_vul.c
1 void page_cache_ra_order(struct readahead_control *ractl,
2 		struct file_ra_state *ra, unsigned int new_order)
5 	pgoff_t index = readahead_index(ractl);
7 	pgoff_t mark = index + ra->size - ra->async_size;

```
which has a vulnerability among CWE-457 and among lines:
```
7 	pgoff_t mark = index + ra->size - ra->async_size;
```
Please generate five possible patches for the vulnerability.
A: The patch can be done in two steps.
Step 1. 