On 03.10.2015 [07:35:09 +1000], Benjamin Herrenschmidt wrote: > On Fri, 2015-10-02 at 14:04 -0700, Nishanth Aravamudan wrote: > > Right, I did start with your advice and tried that approach, but it > > turned out I was wrong about the actual issue at the time. The problem > > for NVMe isn't actually the starting address alignment (which it can > > handle not being aligned to the device's page size). It doesn't handle > > (addr + len % dev_page_size != 0). That is, it's really a length > > alignment issue. > > > > It seems incredibly device specific to have a an API into the DMA code > > to request an end alignment -- no other device seems to have this > > issue/design. If you think that's better, I can fiddle with that > > instead. > > > > Sorry, I should have called this out better as an alternative > > consideration. > > Nah it's fine. Ok. Also adding the alignment requirement to the API > would have been a much more complex patch since it would have had to > be implemented for all archs. > > I think your current solution is fine.
Great, thanks. Also, while it's possible an alignment API would be more performant...we're already not using DDW on Power in this case, performance is not a primary concern. We want to simply be functional/correct in this configuration. -Nish -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
