[PATCH 6.18 200/227] rust: irq: always inline functions using build_assert with arguments

Greg Kroah-Hartman
2026-01-28T16:01:23Z

From: Alexandre Courbot <acourbot@nvidia.com>

commit 5d9c4c272ba06055d19e05c2a02e16e58acc8943 upstream.

`build_assert` relies on the compiler to optimize out its error path.
Functions using it with its arguments must thus always be inlined,
otherwise the error path of `build_assert` might not be optimized out,
triggering a build error.

Cc: stable@vger.kernel.org
Fixes: 746680ec6696 ("rust: irq: add flags module")
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://patch.msgid.link/20251208-io-build-assert-v3-6-98aded02c1ea@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
rust/kernel/irq/flags.rs | 2 ++
1 file changed, 2 insertions(+)

diff --git a/rust/kernel/irq/flags.rs b/rust/kernel/irq/flags.rs
index adfde96ec47c..d26e25af06ee 100644
--- a/rust/kernel/irq/flags.rs
+++ b/rust/kernel/irq/flags.rs
@@ -96,6 +96,8 @@ pub(crate) fn into_inner(self) -> c_ulong {
self.0
}

+ // Always inline to optimize out error path of `build_assert`.
+ #[inline(always)]
const fn new(value: u32) -> Self {
build_assert!(value as u64 <= c_ulong::MAX as u64);
Self(value as c_ulong)
--
2.52.0