From 359af525750d3c13f2d500bf9425c945c9467ce3 Mon Sep 17 00:00:00 2001
From: Antoni Boucher <bouanto@zoho.com>
Date: Fri, 7 Aug 2026 19:50:12 +0200
Subject: rust: bitfield: always inline test conversions

When using the Rust GCC backend (i.e. `rustc_codegen_gcc`), GCC does not
inline enough these `Bounded::from_expr` calls:

    /usr/bin/x86_64-linux-gnu-ld.bfd: rust/kernel.o: in function `<kernel::num::bounded::Bounded<u16, 2> as core::convert::From<kernel::bitfield::tests::Priority>>::from':
    fake.c:(.text.unlikely+0x7be): undefined reference to `rust_build_error'

    /usr/bin/x86_64-linux-gnu-ld.bfd: rust/kernel.o: in function `<kernel::num::bounded::Bounded<u64, 4> as core::convert::From<kernel::bitfield::tests::MemoryType>>::from':
    fake.c:(.text.unlikely+0x90d): undefined reference to `rust_build_error'

Thus, similar to commit bc197e24a3ac ("rust: num: bounded: Always inline
fits_within and from_expr"), mark them as `#[inline(always)]`.

[ Reworded to add the error and to follow our usual style and sent on
  behalf of Antoni, who found this during his work to support Rust for
  Linux with the GCC backend, i.e. with `rustc_codegen_gcc`. - Miguel ]

Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Antoni Boucher <bouanto@zoho.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Link: https://patch.msgid.link/20260807175012.142083-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 rust/kernel/bitfield.rs | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'rust/kernel/bitfield.rs')

diff --git a/rust/kernel/bitfield.rs b/rust/kernel/bitfield.rs
index 35ede53f2b8e..a0d089423f21 100644
--- a/rust/kernel/bitfield.rs
+++ b/rust/kernel/bitfield.rs
@@ -581,6 +581,7 @@ mod tests {
     }
 
     impl From<MemoryType> for Bounded<u64, 4> {
+        #[inline(always)]
         fn from(mt: MemoryType) -> Bounded<u64, 4> {
             Bounded::from_expr(mt as u64)
         }
@@ -606,6 +607,7 @@ mod tests {
     }
 
     impl From<Priority> for Bounded<u16, 2> {
+        #[inline(always)]
         fn from(p: Priority) -> Bounded<u16, 2> {
             Bounded::from_expr(p as u16)
         }
-- 
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