dma_unmap_sg
dma_unmap_sg(adev->dev, ttm->sg->sgl, ttm->sg->nents, direction);
dma_unmap_sg(attachment->dev, sg->sgl, sg->nents, dir);
dma_unmap_sg(kdev, pages->sgl, pages->nents, PCI_DMA_BIDIRECTIONAL);
dma_unmap_sg(rdev->dev, ttm->sg->sgl, ttm->sg->nents, direction);