int dev_dax_probe()

in device.c [400:474]

• 64 lines of code
• 12 McCabe index (conditional complexity)

int dev_dax_probe(struct dev_dax *dev_dax)
{
	struct dax_device *dax_dev = dev_dax->dax_dev;
	struct device *dev = &dev_dax->dev;
	struct dev_pagemap *pgmap;
	struct inode *inode;
	struct cdev *cdev;
	void *addr;
	int rc, i;

	if (static_dev_dax(dev_dax))  {
		if (dev_dax->nr_range > 1) {
			dev_warn(dev,
				"static pgmap / multi-range device conflict\n");
			return -EINVAL;
		}

		pgmap = dev_dax->pgmap;
	} else {
		if (dev_dax->pgmap) {
			dev_warn(dev,
				 "dynamic-dax with pre-populated page map\n");
			return -EINVAL;
		}

		pgmap = devm_kzalloc(dev,
                       struct_size(pgmap, ranges, dev_dax->nr_range - 1),
                       GFP_KERNEL);
		if (!pgmap)
			return -ENOMEM;

		pgmap->nr_range = dev_dax->nr_range;
		dev_dax->pgmap = pgmap;

		for (i = 0; i < dev_dax->nr_range; i++) {
			struct range *range = &dev_dax->ranges[i].range;
			pgmap->ranges[i] = *range;
		}
	}

	for (i = 0; i < dev_dax->nr_range; i++) {
		struct range *range = &dev_dax->ranges[i].range;

		if (!devm_request_mem_region(dev, range->start,
					range_len(range), dev_name(dev))) {
			dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve range\n",
					i, range->start, range->end);
			return -EBUSY;
		}
	}

	pgmap->type = MEMORY_DEVICE_GENERIC;
	if (dev_dax->align > PAGE_SIZE)
		pgmap->vmemmap_shift =
			order_base_2(dev_dax->align >> PAGE_SHIFT);
	addr = devm_memremap_pages(dev, pgmap);
	if (IS_ERR(addr))
		return PTR_ERR(addr);

	inode = dax_inode(dax_dev);
	cdev = inode->i_cdev;
	cdev_init(cdev, &dax_fops);
	cdev->owner = dev->driver->owner;
	cdev_set_parent(cdev, &dev->kobj);
	rc = cdev_add(cdev, dev->devt, 1);
	if (rc)
		return rc;

	rc = devm_add_action_or_reset(dev, dev_dax_cdev_del, cdev);
	if (rc)
		return rc;

	run_dax(dax_dev);
	return devm_add_action_or_reset(dev, dev_dax_kill, dev_dax);
}