On Thu, Apr 27, 2023 at 07:09:38AM +0000, Liu, Yi L wrote: > > > @@ -50,7 +53,7 @@ struct iommufd_object *_iommufd_object_alloc(struct > > > iommufd_ctx *ictx, > > > * before calling iommufd_object_finalize(). > > > */ > > > rc = xa_alloc(&ictx->objects, &obj->id, XA_ZERO_ENTRY, > > > - xa_limit_32b, GFP_KERNEL_ACCOUNT); > > > + iommufd_xa_limit_32b, GFP_KERNEL_ACCOUNT); > > > > Just direct use XA_LIMIT() here. > > Ok. > > > btw do we need a contract so vfio can learn 0 and -1 are reserved or > > fine to have a fixed assumption in later patches? > > I doubt how to do it. ☹ @Jason? What about your opinion? It is probably fine to use xa_limit_31b and just say that -ve values are reserved in a comment near the define for 0 Jason