FUJITA Tomonori wrote: > On Tue, 15 Jan 2008 21:10:50 +0100 (CET) > Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx> wrote: >> +++ linux/drivers/firewire/fw-sbp2.c >> @@ -1107,9 +1107,9 @@ sbp2_map_scatterlist(struct sbp2_command >> * elements larger than 65535 bytes, some IOMMUs may merge sg elements >> * during DMA mapping, and Linux currently doesn't prevent this. >> */ > > On a relate note, I fixed the IOMMU merge issue. The patches have been > -mm though I'm not sure whether they will go into v2.6.25. The patches > enable you to remove the following workaround if you configure the > maximum sg element length. Thanks, I will keep an eye on it. > From a quick look, fw-sbp2 uses scsi-ml in a different way so it would > be a bit trick to configure the maximum sg element length. > > You call dma_map_sg with pci_dev::dev but don't call scsi_add_host > with pci_dev::dev. > > If you set the maximum sg element length to pci_dev::dev, and then > call scsi_add_host with it, the block layer and the IOMMU send you > proper size sg elements. At the moment, the Scsi_Host instances map 1:1 to SBP-2 target instances. I have to think about whether we can map it to FireWire controller instances instead. (Besides, the s/g element length limitation is actually a limitation of the SBP-2 protocol, not of FireWire PCI cards.) -- Stefan Richter -=====-==--- ---= =--== http://arcgraph.de/sr/ - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
