int w1_add_master_device()

in w1_int.c [93:171]

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

int w1_add_master_device(struct w1_bus_master *master)
{
	struct w1_master *dev, *entry;
	int retval = 0;
	struct w1_netlink_msg msg;
	int id, found;

	/* validate minimum functionality */
	if (!(master->touch_bit && master->reset_bus) &&
	    !(master->write_bit && master->read_bit) &&
	    !(master->write_byte && master->read_byte && master->reset_bus)) {
		pr_err("w1_add_master_device: invalid function set\n");
		return(-EINVAL);
	}

	/* Lock until the device is added (or not) to w1_masters. */
	mutex_lock(&w1_mlock);
	/* Search for the first available id (starting at 1). */
	id = 0;
	do {
		++id;
		found = 0;
		list_for_each_entry(entry, &w1_masters, w1_master_entry) {
			if (entry->id == id) {
				found = 1;
				break;
			}
		}
	} while (found);

	dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
		&w1_master_driver, &w1_master_device);
	if (!dev) {
		mutex_unlock(&w1_mlock);
		return -ENOMEM;
	}

	retval =  w1_create_master_attributes(dev);
	if (retval) {
		mutex_unlock(&w1_mlock);
		goto err_out_free_dev;
	}

	memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));

	dev->initialized = 1;

	dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
	if (IS_ERR(dev->thread)) {
		retval = PTR_ERR(dev->thread);
		dev_err(&dev->dev,
			 "Failed to create new kernel thread. err=%d\n",
			 retval);
		mutex_unlock(&w1_mlock);
		goto err_out_rm_attr;
	}

	list_add(&dev->w1_master_entry, &w1_masters);
	mutex_unlock(&w1_mlock);

	memset(&msg, 0, sizeof(msg));
	msg.id.mst.id = dev->id;
	msg.type = W1_MASTER_ADD;
	w1_netlink_send(dev, &msg);

	return 0;

#if 0 /* Thread cleanup code, not required currently. */
err_out_kill_thread:
	set_bit(W1_ABORT_SEARCH, &dev->flags);
	kthread_stop(dev->thread);
#endif
err_out_rm_attr:
	w1_destroy_master_attributes(dev);
err_out_free_dev:
	w1_free_dev(dev);

	return retval;
}