static unsigned fill_balloon()

in virtio_balloon.c [211:259]

• 36 lines of code
• 6 McCabe index (conditional complexity)

static unsigned fill_balloon(struct virtio_balloon *vb, size_t num)
{
	unsigned num_allocated_pages;
	unsigned num_pfns;
	struct page *page;
	LIST_HEAD(pages);

	/* We can only do one array worth at a time. */
	num = min(num, ARRAY_SIZE(vb->pfns));

	for (num_pfns = 0; num_pfns < num;
	     num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
		struct page *page = balloon_page_alloc();

		if (!page) {
			dev_info_ratelimited(&vb->vdev->dev,
					     "Out of puff! Can't get %u pages\n",
					     VIRTIO_BALLOON_PAGES_PER_PAGE);
			/* Sleep for at least 1/5 of a second before retry. */
			msleep(200);
			break;
		}

		balloon_page_push(&pages, page);
	}

	mutex_lock(&vb->balloon_lock);

	vb->num_pfns = 0;

	while ((page = balloon_page_pop(&pages))) {
		balloon_page_enqueue(&vb->vb_dev_info, page);

		set_page_pfns(vb, vb->pfns + vb->num_pfns, page);
		vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE;
		if (!virtio_has_feature(vb->vdev,
					VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
			adjust_managed_page_count(page, -1);
		vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE;
	}

	num_allocated_pages = vb->num_pfns;
	/* Did we get any? */
	if (vb->num_pfns != 0)
		tell_host(vb, vb->inflate_vq);
	mutex_unlock(&vb->balloon_lock);

	return num_allocated_pages;
}