On Wed, 24 Oct 2007 07:40:50 -0400 Jeff Garzik <jeff@xxxxxxxxxx> wrote: > FUJITA Tomonori wrote: > > IOMMUs merges scatter/gather segments without considering a low level > > driver's restrictions. The problem is that IOMMUs can't access to the > > limitations because they are in request_queue. > > > > This patchset introduces a new structure, device_dma_parameters, > > including dma information. A pointer to device_dma_parameters is added > > to struct device. The bus specific structures (like pci_dev) includes > > device_dma_parameters. Low level drivers can use dma_set_max_seg_size > > to tell IOMMUs about the restrictions. > > > > We can move more dma stuff in struct device (like dma_mask) to struct > > device_dma_parameters later (needs some cleanups before that). > > > > This includes patches for all the IOMMUs that could merge sg (x86_64, > > ppc, IA64, alpha, sparc64, and parisc) though only the ppc patch was > > tested. The patches for other IOMMUs are only compile tested. > > > > Thanks to everyone for the comments on the previous submission > > to linux-scsi. > > > > This is against 2.6.24-rc1. The same patchset is also available: > > > > git://git.kernel.org/pub/scm/linux/kernel/git/tomo/linux-2.6-misc.git iommu-sg-fixes > > Are you interested in collecting patches to libata that eliminate the > hand-rolled S/G splitting? e.g. now ata_fill_sg() and mv_fill_sg() can > be made much more efficient. Yeah, but ATA has the segment boundary limit too. It's much more tricky than the segment size limit. It makes the IOMMU free space managemet complicated. > Again, thanks for doing this! It's been needed for a long time. My pleasure. - 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
