On Fri, Feb 20, 2026 at 05:08:09PM +0100, Danilo Krummrich wrote: > On Fri Feb 20, 2026 at 9:16 AM CET, Alice Ryhl wrote: > >> > +/// A [`GpuVmBo`] object in the GEM list. > >> > +/// > >> > +/// # Invariants > >> > +/// > >> > +/// Points at a `drm_gpuvm_bo` that contains a valid `T::VmBoData` and > >> > is present in the gem list. > >> > +pub struct GpuVmBoRegistered<T: DriverGpuVm>(NonNull<GpuVmBo<T>>); > >> > >> I know that I proposed to rename this from GpuVmBoResident to > >> GpuVmBoRegistered > >> in a drive-by comment on v3. > >> > >> But now that I have a closer look, I think it would be nice to just have > >> GpuVmBo > >> being the registered one and GpuVmBoAlloc being the pre-allocated one. > >> > >> As it is currently, I think it is bad to ever present a &GpuVmBo to a > >> driver > >> because it implies that we don't know whether it is a pre-allocated one or > >> a > >> "normal", registered one. But we do always know. > > > > Actually, I think GpuVmBo is already the registered one. > > GpuVmBoRegistered is just ARef<GpuVmBo<T>>. > > GpuVmBoAlloc<T> dereferences to GpuVmBo<T>, so currently it is not.
I will drop the Deref impl. > >> For instance, in patch 6 we give out &'op GpuVmBo<T>, but it actually > >> carries > >> the invariant of being registered. > >> > >> Of course, we could fix this by giving out a &'op GpuVmBoRegistered<T> > >> instead, > >> but it would be nice to not have drivers be in touch with a type that can > >> be one > >> or the other. > >> > >> I know that the current GpuVmBo<T> also serves the purpose of storing > >> common > >> code. Maybe we can make it private, call it GpuVmBoInner<T> and have inline > >> forwarding methods for GpuVmBo<T> and GpuVmBoAlloc<T>. This is slightly > >> more > >> overhead in this implementation due to the forwarding methods, but less > >> ambiguity for drivers, which I think is more important. > > > > I think we should keep the current state that GpuVmBo is registered, and > > only GpuVmBoAlloc is not. That is most useful. > > We seem to agree then: What I want is that from a driver perspective there is > only GpuVmBo<T> (which is the registered thing) and GpuVmBoAlloc<T> which is > the > pre-allocated thing, i.e. no separate GpuVmBoRegistered<T> type. So, should we get rid of GpuVmBoRegistered in favor of ARef<GpuVm<T>>? Alice
