# Re: \[PATCH v2 1/9\] cxl: Convert "RBI" to enum

- From: Dan Williams \<hidden\>
- Date: 2021-09-27 23:14:43 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2021/09/9524526
- Thread: https://ratatoskr.run/linux-pci/2021/09/9524493/t.md

```text
Please spell out "register block indicator" in the subject so that the
shortlog remains somewhat readable.

On Thu, Sep 23, 2021 at 10:27 AM Ben Widawsky [ref] wrote:
>
> In preparation for passing around the Register Block Indicator (RBI) as
> a parameter, it is desirable to convert the type to an enum so that the
> interface can use a well defined type checked parameter.

C wouldn't type check this unless it failed an integer conversion,
right? It would need to be a struct to get useful type checking.

I don't mind this for the self documenting properties it has for the
functions that will take this as a parameter, but maybe clarify what
you mean by type checked parameter?

>
> As a result of this change, should future versions of the spec add
> sparsely defined identifiers, it could become a problem if checking for
> invalid identifiers since the code currently checks for the max
> identifier. This is not an issue with current spec, and the algorithm to
> obtain the register blocks will change before those possible additions
> are made.

In general let's not spend changelog space trying to guess what future
specs may or may not do. I.e. I think this text can be dropped,
especially because enums can support sparse number spaces.
```