[PATCH v2] rust: impl_flags: use bit helper in example

[PATCH v2] rust: impl_flags: use bit helper in example

[Kosumi Chan]

Use bit_u32() instead of open-coding shifts in the impl_flags! example.
This demonstrates the checked bit helper and ensures that bit positions
remain within the underlying u32 type.

Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1244
Assisted-by: OpenCode:openai/gpt-5.6-sol
Signed-off-by: Kosumi Chan <chankocyo@gmail.com>
---
Changes in v2:
- Use a full name for the author and Signed-off-by identities.

v1: https://lore.kernel.org/rust-for-linux/20260711071551.3035420-1-chankocyo@gmail.com/

 rust/kernel/impl_flags.rs | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/rust/kernel/impl_flags.rs b/rust/kernel/impl_flags.rs
index e2bd7639d..fdf44d5ee 100644
--- a/rust/kernel/impl_flags.rs
+++ b/rust/kernel/impl_flags.rs
@@ -19,7 +19,10 @@
 /// # Examples
 ///
 /// ```
-/// use kernel::impl_flags;
+/// use kernel::{
+///     bits::bit_u32,
+///     impl_flags, //
+/// };
 ///
 /// impl_flags!(
 ///     /// Represents multiple permissions.
@@ -30,13 +33,13 @@
 ///     #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 ///     pub enum Permission {
 ///         /// Read permission.
-///         Read = 1 << 0,
+///         Read = bit_u32(0),
 ///
 ///         /// Write permission.
-///         Write = 1 << 1,
+///         Write = bit_u32(1),
 ///
 ///         /// Execute permission.
-///         Execute = 1 << 2,
+///         Execute = bit_u32(2),
 ///     }
 /// );
 ///

base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482
-- 
2.54.0

Re: [PATCH v2] rust: impl_flags: use bit helper in example

[Miguel Ojeda]

On Sat, Jul 11, 2026 at 10:23 AM Kosumi Chan <chankocyo@gmail.com> wrote:
>
> Use bit_u32() instead of open-coding shifts in the impl_flags! example.
> This demonstrates the checked bit helper and ensures that bit positions
> remain within the underlying u32 type.
>
> Suggested-by: Miguel Ojeda <ojeda@kernel.org>
> Link: https://github.com/Rust-for-Linux/linux/issues/1244
> Assisted-by: OpenCode:openai/gpt-5.6-sol
> Signed-off-by: Kosumi Chan <chankocyo@gmail.com>

Looks fine, thanks.

I think I will add:

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/rust-for-linux/2026071054-hazing-antirust-8e40@gregkh/

since Greg suggested the original change/idea even if not the one here.

Cheers,
Miguel

Re: [PATCH v2] rust: impl_flags: use bit helper in example

[Alexandre Courbot]

On Sat Jul 11, 2026 at 5:23 PM JST, Kosumi Chan wrote:
> Use bit_u32() instead of open-coding shifts in the impl_flags! example.
> This demonstrates the checked bit helper and ensures that bit positions
> remain within the underlying u32 type.
>
> Suggested-by: Miguel Ojeda <ojeda@kernel.org>
> Link: https://github.com/Rust-for-Linux/linux/issues/1244
> Assisted-by: OpenCode:openai/gpt-5.6-sol
> Signed-off-by: Kosumi Chan <chankocyo@gmail.com>

Why not. :)

Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>