Re: [PATCH v6] rust: kernel: add support for bits/genmask macros

[Daniel Almeida <daniel.almeida@collabora.com>]

Hi Alex,

> On 16 Jun 2025, at 11:52, Alexandre Courbot <acourbot@nvidia.com> wrote:
> 
> On Mon Jun 16, 2025 at 11:45 PM JST, Daniel Almeida wrote:
>> 
>> 
>>> On 16 Jun 2025, at 11:42, Daniel Almeida <daniel.almeida@collabora.com> wrote:
>>> 
>>> Hi Boqun,
>>> 
>>>> 
>>>> We should tell/educate people to do the right thing, if a..b is not
>>>> inclusive in Rust, then we should treat them as non-inclusive in Rust
>>>> kernel code. Otherwise you create confusion for no reason. My assumption
>>>> is that most people will ask "what's the right way to do this" first
>>>> instead of replicating the old way.
>>>> 
>>>> Regards,
>>>> Boqun
>>>> 
>>> 
>>> This is just my opinion, of course:
>>> 
>>> I _hardly_ believe this will be the case. When people see genmask and two
>>> numbers, they expect the range to be inclusive, full stop (at least IMHO). That's how it has
>>> worked for decades, so it’s only natural to expect this behavior to transfer over.
>>> 
>>> However, I do understand and agree with your point, and I will change the
>>> implementation here to comply. Perhaps we can use some markdown to alert users?
>>> 
>>> — Daniel
>> 
>> Or better yet, perhaps we should only support a..=b.
> 
> ... or just drop the ranges and do as Daniel initially did, using two
> arguments. But I agree with Boqun that we should not deviate from the
> official interpretation of ranges if we use them - the fact that `Range`
> is exclusive on its upper bound is documented and a property of the type
> itself.

By the same token, I agree that we should use ranges instead of two arguments,
if said two arguments represent a range anyways. So my vote is for a..=b JFYI.