static int pmcraid_copy_sglist(
	struct pmcraid_sglist *sglist,
	unsigned long buffer,
	u32 len,
	int direction
)
{
	struct scatterlist *scatterlist;
	void *kaddr;
	int bsize_elem;
	int i;
	int rc = 0;

	/* Determine the actual number of bytes per element */
	bsize_elem = PAGE_SIZE * (1 << sglist->order);

	scatterlist = sglist->scatterlist;

	for (i = 0; i < (len / bsize_elem); i++, buffer += bsize_elem) {
		struct page *page = sg_page(&scatterlist[i]);

		kaddr = kmap(page);
		if (direction == DMA_TO_DEVICE)
			rc = __copy_from_user(kaddr,
					      (void *)buffer,
					      bsize_elem);
		else
			rc = __copy_to_user((void *)buffer, kaddr, bsize_elem);

		kunmap(page);

		if (rc) {
			pmcraid_err("failed to copy user data into sg list\n");
			return -EFAULT;
		}

		scatterlist[i].length = bsize_elem;
	}

	if (len % bsize_elem) {
		struct page *page = sg_page(&scatterlist[i]);

		kaddr = kmap(page);

		if (direction == DMA_TO_DEVICE)
			rc = __copy_from_user(kaddr,
					      (void *)buffer,
					      len % bsize_elem);
		else
			rc = __copy_to_user((void *)buffer,
					    kaddr,
					    len % bsize_elem);

		kunmap(page);

		scatterlist[i].length = len % bsize_elem;
	}

	if (rc) {
		pmcraid_err("failed to copy user data into sg list\n");
		rc = -EFAULT;
	}

	return rc;
}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.