static int uio_mmap()

in uio.c [762:816]

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

static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
{
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;
	int mi;
	unsigned long requested_pages, actual_pages;
	int ret = 0;

	if (vma->vm_end < vma->vm_start)
		return -EINVAL;

	vma->vm_private_data = idev;

	mutex_lock(&idev->info_lock);
	if (!idev->info) {
		ret = -EINVAL;
		goto out;
	}

	mi = uio_find_mem_index(vma);
	if (mi < 0) {
		ret = -EINVAL;
		goto out;
	}

	requested_pages = vma_pages(vma);
	actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
			+ idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
	if (requested_pages > actual_pages) {
		ret = -EINVAL;
		goto out;
	}

	if (idev->info->mmap) {
		ret = idev->info->mmap(idev->info, vma);
		goto out;
	}

	switch (idev->info->mem[mi].memtype) {
	case UIO_MEM_IOVA:
	case UIO_MEM_PHYS:
		ret = uio_mmap_physical(vma);
		break;
	case UIO_MEM_LOGICAL:
	case UIO_MEM_VIRTUAL:
		ret = uio_mmap_logical(vma);
		break;
	default:
		ret = -EINVAL;
	}

 out:
	mutex_unlock(&idev->info_lock);
	return ret;
}