On Sun, 2008-01-13 at 16:29 +0000, Alan Cox wrote: > > Yes, I concur for the short term. The other two possible courses of > > action either involve long discussions (the different device one) or > > you'll never quite be sure you got all the paths (the GFP_DMA32 one). > > At least with this one, you know everything will work. > > The different device one is tricky because the PCI layer is involved in > mapping on some systems so you can't just magic up a platform device for > it. Putting a mask on the block queue might perhaps work as a model > which avoids breaking stuff by suprise, with the device left at 32bit > masking. Actually, you might be able to ... that's why I'm suggesting it. There are two pieces of information the arch layer needs to know: what is the dma_mask and where is the iommu/bridge/whatever. When we went to the generic dma_map_ API on parisc, we found you simply get the one from struct device and for the other you walk up the device tree until you find what you're looking for. I'm not suggesting we invent a dummy pci_device ... I'm suggesting we dma_map on the existing scsi_device, which is properly parented to the pci_device. The problem with this approach will be any architecture which blindly expects dma_map converts to pci_dma_map; however, I'm not sure we have any of those left. James - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
