On Tue, 25 Sep 2007 10:39:17 +0200 Hannes Reinecke <[EMAIL PROTECTED]> wrote:
> Hi Tomo, > > FUJITA Tomonori wrote: > > On Sat, 8 Sep 2007 13:00:36 +0100 > > Christoph Hellwig <[EMAIL PROTECTED]> wrote: > > > >> On Sat, Sep 08, 2007 at 07:32:27AM -0400, Jeff Garzik wrote: > >>> FUJITA Tomonori wrote: > >>>> Yeah, iommu code ignores the lld limitations (the problem is that the > >>>> lld limitations are in request_queue and iommu code can't access to > >>>> request_queue). There is no way to tell iommu code about the lld > >>>> limitations. > >>> > >>> This fact very much wants fixing. > >> > >> Absolutely. Unfortunately everyone wastes their time on creating > >> workarounds > >> instead of fixing the underlying problem. > > > > Any ideas on how to fix this? > > > > I chatted to Jens and James on this last week. > > > > - we could just copies the lld limitations to device structure. it's > > hacky but device structure already has hacky stuff. > > > > - we could just link device structure to request_queue structure so > > that iommu code can see request_queue structure. > > > > - we could remove the lld limitations in request_queue strucutre and > > have a new strucutre (something like struct io_restrictions). then > > somehow we could link the new structure with request_queue and device > > strucutres. > > > I'd prefer the latter. These struct io_restrictions could then be used > by dm (which has it's own version right now) to merge queue capabilities. Yeah, we could nicely handle lld's restrictions (especially with stacking devices). But iommu code needs only max_segment_size and seg_boundary_mask, right? If so, the first simple approach to add two values to device structure is not so bad, I think. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
