static ssize_t occ_write()

in fsi-occ.c [138:194]

• 34 lines of code
• 7 McCabe index (conditional complexity)

static ssize_t occ_write(struct file *file, const char __user *buf,
			 size_t len, loff_t *offset)
{
	struct occ_client *client = file->private_data;
	size_t rlen, data_length;
	ssize_t rc;
	u8 *cmd;

	if (!client)
		return -ENODEV;

	if (len > (OCC_CMD_DATA_BYTES + 3) || len < 3)
		return -EINVAL;

	mutex_lock(&client->lock);

	/* Construct the command */
	cmd = client->buffer;

	/*
	 * Copy the user command (assume user data follows the occ command
	 * format)
	 * byte 0: command type
	 * bytes 1-2: data length (msb first)
	 * bytes 3-n: data
	 */
	if (copy_from_user(&cmd[1], buf, len)) {
		rc = -EFAULT;
		goto done;
	}

	/* Extract data length */
	data_length = (cmd[2] << 8) + cmd[3];
	if (data_length > OCC_CMD_DATA_BYTES) {
		rc = -EINVAL;
		goto done;
	}

	/* Submit command; 4 bytes before the data and 2 bytes after */
	rlen = PAGE_SIZE;
	rc = fsi_occ_submit(client->occ->dev, cmd, data_length + 6, cmd,
			    &rlen);
	if (rc)
		goto done;

	/* Set read tracking data */
	client->data_size = rlen;
	client->read_offset = 0;

	/* Done */
	rc = len;

 done:
	mutex_unlock(&client->lock);

	return rc;
}