[PATCH] cpufreq: rust: Use C FFI types in bios_limit_callback

[PATCH] cpufreq: rust: Use C FFI types in bios_limit_callback

[Abhinav Ananthu]

Update the bios_limit_callback function to use C FFI-compatible types
(kernel::ffi::c_int and kernel::ffi::c_uint) for its parameters and return
value. This ensures ABI compatibility with the corresponding C callback
signature.

Reported-by: Miguel Ojeda <ojeda@kernel.org>
Closes: https://lore.kernel.org/rust-for-linux/CANiq72=WpuGELzLbH-fxdOeJy9fiDFwatz6ynERDh=HP2z2MBw@mail.gmail.com/.
Signed-off-by: Abhinav Ananthu <abhinav.ogl@gmail.com>
---
 rust/kernel/cpufreq.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs
index b0a9c6182aec..7ef2f64d8f34 100644
--- a/rust/kernel/cpufreq.rs
+++ b/rust/kernel/cpufreq.rs
@@ -1277,7 +1277,7 @@ extern "C" fn update_limits_callback(ptr: *mut bindings::cpufreq_policy) {
     /// Driver's `bios_limit` callback.
     ///
     /// SAFETY: Called from C. Inputs must be valid pointers.
-    extern "C" fn bios_limit_callback(cpu: i32, limit: *mut u32) -> kernel::ffi::c_int {
+    extern "C" fn bios_limit_callback(cpu: kernel::ffi::c_int, limit: *mut kernel::ffi::c_uint) -> kernel::ffi::c_int {
         from_result(|| {
             let mut policy = PolicyCpu::from_cpu(cpu as u32)?;
 
-- 
2.34.1

Re: [PATCH] cpufreq: rust: Use C FFI types in bios_limit_callback

[Benno Lossin]

On Thu Jun 12, 2025 at 8:09 AM CEST, Abhinav Ananthu wrote:
> Update the bios_limit_callback function to use C FFI-compatible types
> (kernel::ffi::c_int and kernel::ffi::c_uint) for its parameters and return
> value. This ensures ABI compatibility with the corresponding C callback
> signature.
>
> Reported-by: Miguel Ojeda <ojeda@kernel.org>
> Closes: https://lore.kernel.org/rust-for-linux/CANiq72=WpuGELzLbH-fxdOeJy9fiDFwatz6ynERDh=HP2z2MBw@mail.gmail.com/.
> Signed-off-by: Abhinav Ananthu <abhinav.ogl@gmail.com>
> ---
>  rust/kernel/cpufreq.rs | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs
> index b0a9c6182aec..7ef2f64d8f34 100644
> --- a/rust/kernel/cpufreq.rs
> +++ b/rust/kernel/cpufreq.rs
> @@ -1277,7 +1277,7 @@ extern "C" fn update_limits_callback(ptr: *mut bindings::cpufreq_policy) {
>      /// Driver's `bios_limit` callback.
>      ///
>      /// SAFETY: Called from C. Inputs must be valid pointers.
> -    extern "C" fn bios_limit_callback(cpu: i32, limit: *mut u32) -> kernel::ffi::c_int {
> +    extern "C" fn bios_limit_callback(cpu: kernel::ffi::c_int, limit: *mut kernel::ffi::c_uint) -> kernel::ffi::c_int {

This file imports the kernel's prelude, so you should be able to just
use `c_int` and `c_uint` instead of their qualified names.

---
Cheers,
Benno

>          from_result(|| {
>              let mut policy = PolicyCpu::from_cpu(cpu as u32)?;
>  

[PATCHv2 rust-for-linux] fix : Update the bios_limit_callback to use

[Abhinav Ananthu]

PATCH(v1)
Update the bios_limit_callback function to use C FFI-compatible types
(kernel::ffi::c_int and kernel::ffi::c_uint) for its parameters and return
value. This ensures ABI compatibility with the corresponding C callback
signature.

PATCH(v2)
updated the `bios_limit_callback` function to use `c_int` and `c_uint` directly
via the prelude instead of the fully-qualified `kernel::ffi::*` paths.

Reported-by: Miguel Ojeda <ojeda@kernel.org>
Closes: https://lore.kernel.org/rust-for-linux/CANiq72=WpuGELzLbH-fxdOeJy9fiDFwatz6ynERDh=HP2z2MBw@mail.gmail.com/.
Signed-off-by: Abhinav Ananthu <abhinav.ogl@gmail.com>
---
 rust/kernel/cpufreq.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs
index b0a9c6182aec..e97607ed86c2 100644
--- a/rust/kernel/cpufreq.rs
+++ b/rust/kernel/cpufreq.rs
@@ -1277,7 +1277,7 @@ extern "C" fn update_limits_callback(ptr: *mut bindings::cpufreq_policy) {
     /// Driver's `bios_limit` callback.
     ///
     /// SAFETY: Called from C. Inputs must be valid pointers.
-    extern "C" fn bios_limit_callback(cpu: i32, limit: *mut u32) -> kernel::ffi::c_int {
+    extern "C" fn bios_limit_callback(cpu: c_int, limit: *mut c_uint) -> c_int {
         from_result(|| {
             let mut policy = PolicyCpu::from_cpu(cpu as u32)?;
 
-- 
2.34.1

Re: [PATCHv2 rust-for-linux] fix : Update the bios_limit_callback to use

[Miguel Ojeda]

On Thu, Jun 12, 2025 at 10:47 AM Abhinav Ananthu <abhinav.ogl@gmail.com> wrote:
>
> PATCH(v1)
> Update the bios_limit_callback function to use C FFI-compatible types
> (kernel::ffi::c_int and kernel::ffi::c_uint) for its parameters and return
> value. This ensures ABI compatibility with the corresponding C callback
> signature.
>
> PATCH(v2)
> updated the `bios_limit_callback` function to use `c_int` and `c_uint` directly
> via the prelude instead of the fully-qualified `kernel::ffi::*` paths.
>
> Reported-by: Miguel Ojeda <ojeda@kernel.org>
> Closes: https://lore.kernel.org/rust-for-linux/CANiq72=WpuGELzLbH-fxdOeJy9fiDFwatz6ynERDh=HP2z2MBw@mail.gmail.com/.
> Signed-off-by: Abhinav Ananthu <abhinav.ogl@gmail.com>

Cc'ing Viresh/Rafael/cpufreq, since this is on their subsystem (please
see the entry in the `MAINTAINERS` file for `rust/kernel/cpufreq.rs`).

Also, please note that the changelog goes below the `---` line. The
commit message (above the `---` line) should explain the "what" and
the "why" of the current proposed changes, not other versions.

Finally, the title would normally have been something like:

    [PATCH v2] rust: cpufreq: ...

Thanks for the patch!

Cheers,
Miguel