static ssize_t sbefifo_user_read()

in fsi-sbefifo.c [802:851]

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

static ssize_t sbefifo_user_read(struct file *file, char __user *buf,
				 size_t len, loff_t *offset)
{
	struct sbefifo_user *user = file->private_data;
	struct sbefifo *sbefifo;
	struct iov_iter resp_iter;
        struct iovec resp_iov;
	size_t cmd_len;
	int rc;

	if (!user)
		return -EINVAL;
	sbefifo = user->sbefifo;
	if (len & 3)
		return -EINVAL;

	mutex_lock(&user->file_lock);

	/* Cronus relies on -EAGAIN after a short read */
	if (user->pending_len == 0) {
		rc = -EAGAIN;
		goto bail;
	}
	if (user->pending_len < 8) {
		rc = -EINVAL;
		goto bail;
	}
	cmd_len = user->pending_len >> 2;

	/* Prepare iov iterator */
	resp_iov.iov_base = buf;
	resp_iov.iov_len = len;
	iov_iter_init(&resp_iter, WRITE, &resp_iov, 1, len);

	/* Perform the command */
	rc = mutex_lock_interruptible(&sbefifo->lock);
	if (rc)
		goto bail;
	rc = __sbefifo_submit(sbefifo, user->pending_cmd, cmd_len, &resp_iter);
	mutex_unlock(&sbefifo->lock);
	if (rc < 0)
		goto bail;

	/* Extract the response length */
	rc = len - iov_iter_count(&resp_iter);
 bail:
	sbefifo_release_command(user);
	mutex_unlock(&user->file_lock);
	return rc;
}