int w1_attach_slave_device()

in w1.c [720:784]

• 53 lines of code
• 4 McCabe index (conditional complexity)

int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
{
	struct w1_slave *sl;
	struct w1_family *f;
	int err;
	struct w1_netlink_msg msg;

	sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
	if (!sl) {
		dev_err(&dev->dev,
			 "%s: failed to allocate new slave device.\n",
			 __func__);
		return -ENOMEM;
	}


	sl->owner = THIS_MODULE;
	sl->master = dev;
	set_bit(W1_SLAVE_ACTIVE, &sl->flags);

	memset(&msg, 0, sizeof(msg));
	memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
	atomic_set(&sl->refcnt, 1);
	atomic_inc(&sl->master->refcnt);
	dev->slave_count++;
	dev_info(&dev->dev, "Attaching one wire slave %02x.%012llx crc %02x\n",
		  rn->family, (unsigned long long)rn->id, rn->crc);

	/* slave modules need to be loaded in a context with unlocked mutex */
	mutex_unlock(&dev->mutex);
	request_module("w1-family-0x%02X", rn->family);
	mutex_lock(&dev->mutex);

	spin_lock(&w1_flock);
	f = w1_family_registered(rn->family);
	if (!f) {
		f= &w1_default_family;
		dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
			  rn->family, rn->family,
			  (unsigned long long)rn->id, rn->crc);
	}
	__w1_family_get(f);
	spin_unlock(&w1_flock);

	sl->family = f;

	err = __w1_attach_slave_device(sl);
	if (err < 0) {
		dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
			 sl->name);
		dev->slave_count--;
		w1_family_put(sl->family);
		atomic_dec(&sl->master->refcnt);
		kfree(sl);
		return err;
	}

	sl->ttl = dev->slave_ttl;

	memcpy(msg.id.id, rn, sizeof(msg.id));
	msg.type = W1_SLAVE_ADD;
	w1_netlink_send(dev, &msg);

	return 0;
}