static int translate_desc()

in vhost.c [2037:2080]

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

static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
			  struct iovec iov[], int iov_size, int access)
{
	const struct vhost_iotlb_map *map;
	struct vhost_dev *dev = vq->dev;
	struct vhost_iotlb *umem = dev->iotlb ? dev->iotlb : dev->umem;
	struct iovec *_iov;
	u64 s = 0;
	int ret = 0;

	while ((u64)len > s) {
		u64 size;
		if (unlikely(ret >= iov_size)) {
			ret = -ENOBUFS;
			break;
		}

		map = vhost_iotlb_itree_first(umem, addr, addr + len - 1);
		if (map == NULL || map->start > addr) {
			if (umem != dev->iotlb) {
				ret = -EFAULT;
				break;
			}
			ret = -EAGAIN;
			break;
		} else if (!(map->perm & access)) {
			ret = -EPERM;
			break;
		}

		_iov = iov + ret;
		size = map->size - addr + map->start;
		_iov->iov_len = min((u64)len - s, size);
		_iov->iov_base = (void __user *)(unsigned long)
				 (map->addr + addr - map->start);
		s += size;
		addr += size;
		++ret;
	}

	if (ret == -EAGAIN)
		vhost_iotlb_miss(vq, addr, access);
	return ret;
}