On Thu, 2022-10-20 at 08:05 -0300, Jason Gunthorpe wrote: > On Thu, Oct 20, 2022 at 10:51:10AM +0200, Niklas Schnelle wrote: > > > Ok that makes sense thanks for the explanation. So yes my assessment is > > still that in this situation the IOTLB flush is architected to return > > an error that we can ignore. Not the most elegant I admit but at least > > it's simple. Alternatively I guess we could use call_rcu() to do the > > zpci_unregister_ioat() but I'm not sure how to then make sure that a > > subsequent zpci_register_ioat() only happens after that without adding > > too much more logic. > > This won't work either as the domain could have been freed before the > call_rcu() happens, the domain needs to be detached synchronously > > Jason Yeah right, that is basically the same issue I was thinking of for a subsequent zpci_register_ioat(). What about the obvious one. Just call synchronize_rcu() before zpci_unregister_ioat()?
