* Convert an address in a kernel buffer to a bus/phys/dma address.
* This work *only* for memory fragments part of lp->page_vaddr,
* because it was properly DMA allocated via pci_alloc_consistent(),
* Convert an address in a kernel buffer to a bus/phys/dma address.
* This work *only* for memory fragments part of lp->page_vaddr,
* because it was properly DMA allocated via pci_alloc_consistent(),