static int vfio_iommu_type1_pin_pages()

in vfio_iommu_type1.c [829:949]

• 88 lines of code
• 21 McCabe index (conditional complexity)

static int vfio_iommu_type1_pin_pages(void *iommu_data,
				      struct iommu_group *iommu_group,
				      unsigned long *user_pfn,
				      int npage, int prot,
				      unsigned long *phys_pfn)
{
	struct vfio_iommu *iommu = iommu_data;
	struct vfio_iommu_group *group;
	int i, j, ret;
	unsigned long remote_vaddr;
	struct vfio_dma *dma;
	bool do_accounting;
	dma_addr_t iova;

	if (!iommu || !user_pfn || !phys_pfn)
		return -EINVAL;

	/* Supported for v2 version only */
	if (!iommu->v2)
		return -EACCES;

	mutex_lock(&iommu->lock);

	/*
	 * Wait for all necessary vaddr's to be valid so they can be used in
	 * the main loop without dropping the lock, to avoid racing vs unmap.
	 */
again:
	if (iommu->vaddr_invalid_count) {
		for (i = 0; i < npage; i++) {
			iova = user_pfn[i] << PAGE_SHIFT;
			ret = vfio_find_dma_valid(iommu, iova, PAGE_SIZE, &dma);
			if (ret < 0)
				goto pin_done;
			if (ret == WAITED)
				goto again;
		}
	}

	/* Fail if notifier list is empty */
	if (!iommu->notifier.head) {
		ret = -EINVAL;
		goto pin_done;
	}

	/*
	 * If iommu capable domain exist in the container then all pages are
	 * already pinned and accounted. Accounting should be done if there is no
	 * iommu capable domain in the container.
	 */
	do_accounting = list_empty(&iommu->domain_list);

	for (i = 0; i < npage; i++) {
		struct vfio_pfn *vpfn;

		iova = user_pfn[i] << PAGE_SHIFT;
		dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
		if (!dma) {
			ret = -EINVAL;
			goto pin_unwind;
		}

		if ((dma->prot & prot) != prot) {
			ret = -EPERM;
			goto pin_unwind;
		}

		vpfn = vfio_iova_get_vfio_pfn(dma, iova);
		if (vpfn) {
			phys_pfn[i] = vpfn->pfn;
			continue;
		}

		remote_vaddr = dma->vaddr + (iova - dma->iova);
		ret = vfio_pin_page_external(dma, remote_vaddr, &phys_pfn[i],
					     do_accounting);
		if (ret)
			goto pin_unwind;

		ret = vfio_add_to_pfn_list(dma, iova, phys_pfn[i]);
		if (ret) {
			if (put_pfn(phys_pfn[i], dma->prot) && do_accounting)
				vfio_lock_acct(dma, -1, true);
			goto pin_unwind;
		}

		if (iommu->dirty_page_tracking) {
			unsigned long pgshift = __ffs(iommu->pgsize_bitmap);

			/*
			 * Bitmap populated with the smallest supported page
			 * size
			 */
			bitmap_set(dma->bitmap,
				   (iova - dma->iova) >> pgshift, 1);
		}
	}
	ret = i;

	group = vfio_iommu_find_iommu_group(iommu, iommu_group);
	if (!group->pinned_page_dirty_scope) {
		group->pinned_page_dirty_scope = true;
		iommu->num_non_pinned_groups--;
	}

	goto pin_done;

pin_unwind:
	phys_pfn[i] = 0;
	for (j = 0; j < i; j++) {
		dma_addr_t iova;

		iova = user_pfn[j] << PAGE_SHIFT;
		dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
		vfio_unpin_page_external(dma, iova, do_accounting);
		phys_pfn[j] = 0;
	}
pin_done:
	mutex_unlock(&iommu->lock);
	return ret;
}