static int dev_dax_kmem_probe()

in kmem.c [44:159]

• 79 lines of code
• 14 McCabe index (conditional complexity)

static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
{
	struct device *dev = &dev_dax->dev;
	unsigned long total_len = 0;
	struct dax_kmem_data *data;
	int i, rc, mapped = 0;
	int numa_node;

	/*
	 * Ensure good NUMA information for the persistent memory.
	 * Without this check, there is a risk that slow memory
	 * could be mixed in a node with faster memory, causing
	 * unavoidable performance issues.
	 */
	numa_node = dev_dax->target_node;
	if (numa_node < 0) {
		dev_warn(dev, "rejecting DAX region with invalid node: %d\n",
				numa_node);
		return -EINVAL;
	}

	for (i = 0; i < dev_dax->nr_range; i++) {
		struct range range;

		rc = dax_kmem_range(dev_dax, i, &range);
		if (rc) {
			dev_info(dev, "mapping%d: %#llx-%#llx too small after alignment\n",
					i, range.start, range.end);
			continue;
		}
		total_len += range_len(&range);
	}

	if (!total_len) {
		dev_warn(dev, "rejecting DAX region without any memory after alignment\n");
		return -EINVAL;
	}

	data = kzalloc(struct_size(data, res, dev_dax->nr_range), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	rc = -ENOMEM;
	data->res_name = kstrdup(dev_name(dev), GFP_KERNEL);
	if (!data->res_name)
		goto err_res_name;

	rc = memory_group_register_static(numa_node, total_len);
	if (rc < 0)
		goto err_reg_mgid;
	data->mgid = rc;

	for (i = 0; i < dev_dax->nr_range; i++) {
		struct resource *res;
		struct range range;

		rc = dax_kmem_range(dev_dax, i, &range);
		if (rc)
			continue;

		/* Region is permanently reserved if hotremove fails. */
		res = request_mem_region(range.start, range_len(&range), data->res_name);
		if (!res) {
			dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve region\n",
					i, range.start, range.end);
			/*
			 * Once some memory has been onlined we can't
			 * assume that it can be un-onlined safely.
			 */
			if (mapped)
				continue;
			rc = -EBUSY;
			goto err_request_mem;
		}
		data->res[i] = res;

		/*
		 * Set flags appropriate for System RAM.  Leave ..._BUSY clear
		 * so that add_memory() can add a child resource.  Do not
		 * inherit flags from the parent since it may set new flags
		 * unknown to us that will break add_memory() below.
		 */
		res->flags = IORESOURCE_SYSTEM_RAM;

		/*
		 * Ensure that future kexec'd kernels will not treat
		 * this as RAM automatically.
		 */
		rc = add_memory_driver_managed(data->mgid, range.start,
				range_len(&range), kmem_name, MHP_NID_IS_MGID);

		if (rc) {
			dev_warn(dev, "mapping%d: %#llx-%#llx memory add failed\n",
					i, range.start, range.end);
			release_resource(res);
			kfree(res);
			data->res[i] = NULL;
			if (mapped)
				continue;
			goto err_request_mem;
		}
		mapped++;
	}

	dev_set_drvdata(dev, data);

	return 0;

err_request_mem:
	memory_group_unregister(data->mgid);
err_reg_mgid:
	kfree(data->res_name);
err_res_name:
	kfree(data);
	return rc;
}