On Thu, 12 Sep 2024 11:56:21 +0200, Christoph Hellwig wrote: > > On Sat, Sep 07, 2024 at 11:38:50AM +0100, Andrew Cooper wrote: > > Individual subsystems ought not to know or care about XENPV; it's a > > layering violation. > > Agreed. > > > If the main APIs don't behave properly, then it probably means we've got > > a bug at a lower level (e.g. Xen SWIOTLB is a constant source of fun) > > which is probably affecting other subsystems too. > > > > I think we need to re-analyse the original bug. Right now, the > > behaviour resulting from 53466ebde is worse than what it was trying to fix. > > 53466ebde looks bogus to me, and the commit message doesn't even > try to explain what bad behavior it works around. I'd also like to > state once again that if you think something is broken about dma > allocation or mapping helpers please Cc me and the iommu list. > > Most of the time it's actually the drivers doing something invalid, but > sometimes it is a core dma layer bug or something that needs a proper > API. > > Also while looking at the above commit I noticed the broken fallback > code in snd_dma_noncontig_alloc - get_dma_ops is not for driver use, > and starting with the code queued up for 6.12 will also return NULL > when using dma-iommu for example. Yes, all those are really ugly hacks and have been already removed for 6.12. Let's hope everything works as expected with it. thanks, Takashi
