static ssize_t mbox_test_message_read()

in mailbox-test.c [162:232]

• 56 lines of code
• 8 McCabe index (conditional complexity)

static ssize_t mbox_test_message_read(struct file *filp, char __user *userbuf,
				      size_t count, loff_t *ppos)
{
	struct mbox_test_device *tdev = filp->private_data;
	unsigned long flags;
	char *touser, *ptr;
	int l = 0;
	int ret;

	DECLARE_WAITQUEUE(wait, current);

	touser = kzalloc(MBOX_HEXDUMP_MAX_LEN + 1, GFP_KERNEL);
	if (!touser)
		return -ENOMEM;

	if (!tdev->rx_channel) {
		ret = snprintf(touser, 20, "<NO RX CAPABILITY>\n");
		ret = simple_read_from_buffer(userbuf, count, ppos,
					      touser, ret);
		goto kfree_err;
	}

	add_wait_queue(&tdev->waitq, &wait);

	do {
		__set_current_state(TASK_INTERRUPTIBLE);

		if (mbox_test_message_data_ready(tdev))
			break;

		if (filp->f_flags & O_NONBLOCK) {
			ret = -EAGAIN;
			goto waitq_err;
		}

		if (signal_pending(current)) {
			ret = -ERESTARTSYS;
			goto waitq_err;
		}
		schedule();

	} while (1);

	spin_lock_irqsave(&tdev->lock, flags);

	ptr = tdev->rx_buffer;
	while (l < MBOX_HEXDUMP_MAX_LEN) {
		hex_dump_to_buffer(ptr,
				   MBOX_BYTES_PER_LINE,
				   MBOX_BYTES_PER_LINE, 1, touser + l,
				   MBOX_HEXDUMP_LINE_LEN, true);

		ptr += MBOX_BYTES_PER_LINE;
		l += MBOX_HEXDUMP_LINE_LEN;
		*(touser + (l - 1)) = '\n';
	}
	*(touser + l) = '\0';

	memset(tdev->rx_buffer, 0, MBOX_MAX_MSG_LEN);
	mbox_data_ready = false;

	spin_unlock_irqrestore(&tdev->lock, flags);

	ret = simple_read_from_buffer(userbuf, count, ppos, touser, MBOX_HEXDUMP_MAX_LEN);
waitq_err:
	__set_current_state(TASK_RUNNING);
	remove_wait_queue(&tdev->waitq, &wait);
kfree_err:
	kfree(touser);
	return ret;
}