pci_map_sg
chunk->nsg = pci_map_sg(dev->persist->pdev, chunk->mem,
chunk->nsg = pci_map_sg(dev->persist->pdev, chunk->mem,
chunk->nsg = pci_map_sg(dev->pdev, chunk->mem,
chunk->nsg = pci_map_sg(dev->pdev, chunk->mem,
ret = pci_map_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE);