Re: [PATCH RFC 03/20] ctlv: Add the root family specification and generated files

[Jason Gunthorpe <jgg@ziepe.ca>]

On Tue, Oct 20, 2026 at 02:28:55PM +0200, Jiri Pirko wrote:
> Tue, Oct 20, 2026 at 01:29:45AM +0200, jgg@nvidia.com wrote:
> >> [ ... 238 lines skipped ... ]
> >> --- /dev/null
> >> +++ b/Documentation/ctlv/families.yaml
> >> @@ -0,0 +1,13 @@
> >> +# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
> >> +%YAML 1.2
> >> +---
> >> +# Append-only registry of CTLV family names, indexed by family ID: the entry at
> >> +# index N has family ID N, up to 65535. The root family owns ID 0 and heads the
> >> +# list, and every other entry comes after the entry of the family it inherits.
> >> +# An entry may be marked deprecated, but never reordered, removed, renamed or
> >> +# reused, its position being its wire identity. Every entry must have a
> >> +# specification in specs/<name>.yaml, and is added by the change that adds the
> >> +# implementation. Fixtures under tools/ctlv/tests/ are not registered.
> >> +
> >> +families:
> >> +  - ctlv
> >
> >I see where you are coming from with this, but it is going to be
> >problematic from a global kernel perspective. Given CTLV is imagined
> >as a general tool for any subsystem we cannot control the tree that
> >things merge through. It will not be like netdev where there is one
> >authoritative tree with a linear history.
> >
> >So if Bob and Jane maintainers both add their own subsystems by the
> >time it gets to Linus the IDs will get scrambled, and bisection will
> >be lost. 
> >
> >Either changes to this file must be strictly done in a single tree
> >with shared branches (which is going to be a bit hard process wise)
> >
> >Or we need to put the ID #s here and have some simple process to
> >coordinate them during the development process. Since new families are
> >probably rare it shouldn't be a big deal
> 
> Exactly. Collision is not very likely. Explicit ID or implicit, scramble
> would still happen. And in that case it is resolvable.

I think because of process if it is kept like this we will have to
merge 'dead code' to reserve spots for people doing new work..

But at a minimum this comment above needs a big fat warning not to
change this file without consulting with XYZ to coordinate merging.

Jason