Re: [PATCH 2/4] rust: bitmap: add contiguous area operations

["Gary Guo" <gary@garyguo.net>]

On Mon Jul 6, 2026 at 6:21 PM BST, Alice Ryhl wrote:
> On Mon, Jul 06, 2026 at 12:29:00PM -0400, Yury Norov wrote:
>> All three are the wrappers around the regular outline functions:
>> bitmap_find_next_zero_area_off(), __bitmap_set() and __bitmap_clear().
>> 
>> The inlined version in headers is optimized for small bitmaps. But the
>> optimization is all based on inlining in the C code. It doesn't work
>> if you wrap it with a rust helper.
>> 
>> There was a discussion about the similar find_next_bit(). The function
>> itself is an inliner, but it's a wrapper around the true outlined
>> _find_next_bit(). So we decided to minimize the binder size for that
>> type of functions.
>> 
>> Please, keep the binder minimal unless necessary.
>
> If we can just call __bitmap_clear() without any downsides, then I agree
> we should do that, but we actually do support inlining the helpers now.
> See CONFIG_RUST_INLINE_HELPERS.

bitmap uses __builtin_constant_p which will only work with pure C inlining and
not LLVM IR based inlining.

Best,
Gary