[PATCH v5 1/2] rust: add static_key_false

[Peter Zijlstra]

On Fri, Aug 02, 2024 at 09:31:27AM +0000, Alice Ryhl wrote:
> Add just enough support for static key so that we can use it from
> tracepoints. Tracepoints rely on `static_key_false` even though it is
> deprecated, so we add the same functionality to Rust.
> 
> It is not possible to use the existing C implementation of
> arch_static_branch because it passes the argument `key` to inline
> assembly as an 'i' parameter, so any attempt to add a C helper for this
> function will fail to compile because the value of `key` must be known
> at compile-time.
> 
> One disadvantage of this patch is that it introduces a fair amount of
> duplicated inline assembly. However, this is a limited and temporary
> situation:
> 
> 1. Most inline assembly has no reason to be duplicated like this. It is
>    only needed here due to the use of 'i' parameters.
> 
> 2. Alice will submit a patch along the lines of [1] that removes the
>    duplication. This will happen as a follow-up to this patch series.

You're talking about yourself in the 3rd person?

What's the rush, why not do it right first?