static ssize_t smu_read_command()

in smu.c [1173:1226]

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

static ssize_t smu_read_command(struct file *file, struct smu_private *pp,
				char __user *buf, size_t count)
{
	DECLARE_WAITQUEUE(wait, current);
	struct smu_user_reply_hdr hdr;
	unsigned long flags;
	int size, rc = 0;

	if (!pp->busy)
		return 0;
	if (count < sizeof(struct smu_user_reply_hdr))
		return -EOVERFLOW;
	spin_lock_irqsave(&pp->lock, flags);
	if (pp->cmd.status == 1) {
		if (file->f_flags & O_NONBLOCK) {
			spin_unlock_irqrestore(&pp->lock, flags);
			return -EAGAIN;
		}
		add_wait_queue(&pp->wait, &wait);
		for (;;) {
			set_current_state(TASK_INTERRUPTIBLE);
			rc = 0;
			if (pp->cmd.status != 1)
				break;
			rc = -ERESTARTSYS;
			if (signal_pending(current))
				break;
			spin_unlock_irqrestore(&pp->lock, flags);
			schedule();
			spin_lock_irqsave(&pp->lock, flags);
		}
		set_current_state(TASK_RUNNING);
		remove_wait_queue(&pp->wait, &wait);
	}
	spin_unlock_irqrestore(&pp->lock, flags);
	if (rc)
		return rc;
	if (pp->cmd.status != 0)
		pp->cmd.reply_len = 0;
	size = sizeof(hdr) + pp->cmd.reply_len;
	if (count < size)
		size = count;
	rc = size;
	hdr.status = pp->cmd.status;
	hdr.reply_len = pp->cmd.reply_len;
	if (copy_to_user(buf, &hdr, sizeof(hdr)))
		return -EFAULT;
	size -= sizeof(hdr);
	if (size && copy_to_user(buf + sizeof(hdr), pp->buffer, size))
		return -EFAULT;
	pp->busy = 0;

	return rc;
}