int alias_dpa_busy()

in dimm_devs.c [729:808]

• 58 lines of code
• 18 McCabe index (conditional complexity)

int alias_dpa_busy(struct device *dev, void *data)
{
	resource_size_t map_end, blk_start, new;
	struct blk_alloc_info *info = data;
	struct nd_mapping *nd_mapping;
	struct nd_region *nd_region;
	struct nvdimm_drvdata *ndd;
	struct resource *res;
	unsigned long align;
	int i;

	if (!is_memory(dev))
		return 0;

	nd_region = to_nd_region(dev);
	for (i = 0; i < nd_region->ndr_mappings; i++) {
		nd_mapping  = &nd_region->mapping[i];
		if (nd_mapping->nvdimm == info->nd_mapping->nvdimm)
			break;
	}

	if (i >= nd_region->ndr_mappings)
		return 0;

	ndd = to_ndd(nd_mapping);
	map_end = nd_mapping->start + nd_mapping->size - 1;
	blk_start = nd_mapping->start;

	/*
	 * In the allocation case ->res is set to free space that we are
	 * looking to validate against PMEM aliasing collision rules
	 * (i.e. BLK is allocated after all aliased PMEM).
	 */
	if (info->res) {
		if (info->res->start >= nd_mapping->start
				&& info->res->start < map_end)
			/* pass */;
		else
			return 0;
	}

 retry:
	/*
	 * Find the free dpa from the end of the last pmem allocation to
	 * the end of the interleave-set mapping.
	 */
	align = dpa_align(nd_region);
	if (!align)
		return 0;

	for_each_dpa_resource(ndd, res) {
		resource_size_t start, end;

		if (strncmp(res->name, "pmem", 4) != 0)
			continue;

		start = ALIGN_DOWN(res->start, align);
		end = ALIGN(res->end + 1, align) - 1;
		if ((start >= blk_start && start < map_end)
				|| (end >= blk_start && end <= map_end)) {
			new = max(blk_start, min(map_end, end) + 1);
			if (new != blk_start) {
				blk_start = new;
				goto retry;
			}
		}
	}

	/* update the free space range with the probed blk_start */
	if (info->res && blk_start > info->res->start) {
		info->res->start = max(info->res->start, blk_start);
		if (info->res->start > info->res->end)
			info->res->end = info->res->start - 1;
		return 1;
	}

	info->available -= blk_start - nd_mapping->start;

	return 0;
}