static ssize_t __size_store()

in namespace_devs.c [949:1045]

• 66 lines of code
• 19 McCabe index (conditional complexity)

static ssize_t __size_store(struct device *dev, unsigned long long val)
{
	resource_size_t allocated = 0, available = 0;
	struct nd_region *nd_region = to_nd_region(dev->parent);
	struct nd_namespace_common *ndns = to_ndns(dev);
	struct nd_mapping *nd_mapping;
	struct nvdimm_drvdata *ndd;
	struct nd_label_id label_id;
	u32 flags = 0, remainder;
	int rc, i, id = -1;
	uuid_t *uuid = NULL;

	if (dev->driver || ndns->claim)
		return -EBUSY;

	if (is_namespace_pmem(dev)) {
		struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

		uuid = nspm->uuid;
		id = nspm->id;
	} else if (is_namespace_blk(dev)) {
		struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);

		uuid = nsblk->uuid;
		flags = NSLABEL_FLAG_LOCAL;
		id = nsblk->id;
	}

	/*
	 * We need a uuid for the allocation-label and dimm(s) on which
	 * to store the label.
	 */
	if (uuid_not_set(uuid, dev, __func__))
		return -ENXIO;
	if (nd_region->ndr_mappings == 0) {
		dev_dbg(dev, "not associated with dimm(s)\n");
		return -ENXIO;
	}

	div_u64_rem(val, nd_region->align, &remainder);
	if (remainder) {
		dev_dbg(dev, "%llu is not %ldK aligned\n", val,
				nd_region->align / SZ_1K);
		return -EINVAL;
	}

	nd_label_gen_id(&label_id, uuid, flags);
	for (i = 0; i < nd_region->ndr_mappings; i++) {
		nd_mapping = &nd_region->mapping[i];
		ndd = to_ndd(nd_mapping);

		/*
		 * All dimms in an interleave set, or the base dimm for a blk
		 * region, need to be enabled for the size to be changed.
		 */
		if (!ndd)
			return -ENXIO;

		allocated += nvdimm_allocated_dpa(ndd, &label_id);
	}
	available = nd_region_allocatable_dpa(nd_region);

	if (val > available + allocated)
		return -ENOSPC;

	if (val == allocated)
		return 0;

	val = div_u64(val, nd_region->ndr_mappings);
	allocated = div_u64(allocated, nd_region->ndr_mappings);
	if (val < allocated)
		rc = shrink_dpa_allocation(nd_region, &label_id,
				allocated - val);
	else
		rc = grow_dpa_allocation(nd_region, &label_id, val - allocated);

	if (rc)
		return rc;

	if (is_namespace_pmem(dev)) {
		struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

		nd_namespace_pmem_set_resource(nd_region, nspm,
				val * nd_region->ndr_mappings);
	}

	/*
	 * Try to delete the namespace if we deleted all of its
	 * allocation, this is not the seed or 0th device for the
	 * region, and it is not actively claimed by a btt, pfn, or dax
	 * instance.
	 */
	if (val == 0 && id != 0 && nd_region->ns_seed != dev && !ndns->claim)
		nd_device_unregister(dev, ND_ASYNC);

	return rc;
}