static ssize_t n_vclocks_store()

in ptp_sysfs.c [189:246]

• 45 lines of code
• 10 McCabe index (conditional complexity)

static ssize_t n_vclocks_store(struct device *dev,
			       struct device_attribute *attr,
			       const char *buf, size_t count)
{
	struct ptp_clock *ptp = dev_get_drvdata(dev);
	struct ptp_vclock *vclock;
	int err = -EINVAL;
	u32 num, i;

	if (kstrtou32(buf, 0, &num))
		return err;

	if (mutex_lock_interruptible(&ptp->n_vclocks_mux))
		return -ERESTARTSYS;

	if (num > ptp->max_vclocks) {
		dev_err(dev, "max value is %d\n", ptp->max_vclocks);
		goto out;
	}

	/* Need to create more vclocks */
	if (num > ptp->n_vclocks) {
		for (i = 0; i < num - ptp->n_vclocks; i++) {
			vclock = ptp_vclock_register(ptp);
			if (!vclock)
				goto out;

			*(ptp->vclock_index + ptp->n_vclocks + i) =
				vclock->clock->index;

			dev_info(dev, "new virtual clock ptp%d\n",
				 vclock->clock->index);
		}
	}

	/* Need to delete vclocks */
	if (num < ptp->n_vclocks) {
		i = ptp->n_vclocks - num;
		device_for_each_child_reverse(dev, &i,
					      unregister_vclock);

		for (i = 1; i <= ptp->n_vclocks - num; i++)
			*(ptp->vclock_index + ptp->n_vclocks - i) = -1;
	}

	if (num == 0)
		dev_info(dev, "only physical clock in use now\n");
	else
		dev_info(dev, "guarantee physical clock free running\n");

	ptp->n_vclocks = num;
	mutex_unlock(&ptp->n_vclocks_mux);

	return count;
out:
	mutex_unlock(&ptp->n_vclocks_mux);
	return err;
}