static int nd_pfn_clear_memmap_errors()

in pfn_devs.c [360:420]

• 49 lines of code
• 8 McCabe index (conditional complexity)

static int nd_pfn_clear_memmap_errors(struct nd_pfn *nd_pfn)
{
	struct nd_region *nd_region = to_nd_region(nd_pfn->dev.parent);
	struct nd_namespace_common *ndns = nd_pfn->ndns;
	void *zero_page = page_address(ZERO_PAGE(0));
	struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
	int num_bad, meta_num, rc, bb_present;
	sector_t first_bad, meta_start;
	struct nd_namespace_io *nsio;

	if (nd_pfn->mode != PFN_MODE_PMEM)
		return 0;

	nsio = to_nd_namespace_io(&ndns->dev);
	meta_start = (SZ_4K + sizeof(*pfn_sb)) >> 9;
	meta_num = (le64_to_cpu(pfn_sb->dataoff) >> 9) - meta_start;

	/*
	 * re-enable the namespace with correct size so that we can access
	 * the device memmap area.
	 */
	devm_namespace_disable(&nd_pfn->dev, ndns);
	rc = devm_namespace_enable(&nd_pfn->dev, ndns, le64_to_cpu(pfn_sb->dataoff));
	if (rc)
		return rc;

	do {
		unsigned long zero_len;
		u64 nsoff;

		bb_present = badblocks_check(&nd_region->bb, meta_start,
				meta_num, &first_bad, &num_bad);
		if (bb_present) {
			dev_dbg(&nd_pfn->dev, "meta: %x badblocks at %llx\n",
					num_bad, first_bad);
			nsoff = ALIGN_DOWN((nd_region->ndr_start
					+ (first_bad << 9)) - nsio->res.start,
					PAGE_SIZE);
			zero_len = ALIGN(num_bad << 9, PAGE_SIZE);
			while (zero_len) {
				unsigned long chunk = min(zero_len, PAGE_SIZE);

				rc = nvdimm_write_bytes(ndns, nsoff, zero_page,
							chunk, 0);
				if (rc)
					break;

				zero_len -= chunk;
				nsoff += chunk;
			}
			if (rc) {
				dev_err(&nd_pfn->dev,
					"error clearing %x badblocks at %llx\n",
					num_bad, first_bad);
				return rc;
			}
		}
	} while (bb_present);

	return 0;
}