[PATCH] rust: cpufreq: use c_ types from kernel prelude

From: Abhinav Ananthu
Date: Fri Jun 20 2025 - 04:55:23 EST


Update cpufreq FFI callback signatures to use `c_int` from the `kernel::prelude`,
rather than accessing it explicitly through `kernel::ffi::c_int`.

Although these types are defined in the `ffi` crate, they are re-exported
via `kernel::prelude`. This aligns with the Rust-for-Linux coding
guidelines and ensures proper C ABI compatibility across platforms.

Signed-off-by: Abhinav Ananthu <abhinav.ogl@xxxxxxxxx>
Suggested-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
rust/kernel/cpufreq.rs | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs
index 481a6d2dc362..fda7301c404e 100644
--- a/rust/kernel/cpufreq.rs
+++ b/rust/kernel/cpufreq.rs
@@ -1061,7 +1061,7 @@ impl<T: Driver> Registration<T> {
///
/// - This function may only be called from the cpufreq C infrastructure.
/// - The pointer arguments must be valid pointers.
- unsafe extern "C" fn init_callback(ptr: *mut bindings::cpufreq_policy) -> kernel::ffi::c_int {
+ unsafe extern "C" fn init_callback(ptr: *mut bindings::cpufreq_policy) -> c_int {
from_result(|| {
// SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
// lifetime of `policy`.
@@ -1094,7 +1094,7 @@ impl<T: Driver> Registration<T> {
///
/// - This function may only be called from the cpufreq C infrastructure.
/// - The pointer arguments must be valid pointers.
- unsafe extern "C" fn online_callback(ptr: *mut bindings::cpufreq_policy) -> kernel::ffi::c_int {
+ unsafe extern "C" fn online_callback(ptr: *mut bindings::cpufreq_policy) -> c_int {
from_result(|| {
// SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
// lifetime of `policy`.
@@ -1111,7 +1111,7 @@ impl<T: Driver> Registration<T> {
/// - The pointer arguments must be valid pointers.
unsafe extern "C" fn offline_callback(
ptr: *mut bindings::cpufreq_policy,
- ) -> kernel::ffi::c_int {
+ ) -> c_int {
from_result(|| {
// SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
// lifetime of `policy`.
@@ -1128,7 +1128,7 @@ impl<T: Driver> Registration<T> {
/// - The pointer arguments must be valid pointers.
unsafe extern "C" fn suspend_callback(
ptr: *mut bindings::cpufreq_policy,
- ) -> kernel::ffi::c_int {
+ ) -> c_int {
from_result(|| {
// SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
// lifetime of `policy`.
@@ -1143,7 +1143,7 @@ impl<T: Driver> Registration<T> {
///
/// - This function may only be called from the cpufreq C infrastructure.
/// - The pointer arguments must be valid pointers.
- unsafe extern "C" fn resume_callback(ptr: *mut bindings::cpufreq_policy) -> kernel::ffi::c_int {
+ unsafe extern "C" fn resume_callback(ptr: *mut bindings::cpufreq_policy) -> c_int {
from_result(|| {
// SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
// lifetime of `policy`.
@@ -1173,7 +1173,7 @@ impl<T: Driver> Registration<T> {
/// - The pointer arguments must be valid pointers.
unsafe extern "C" fn verify_callback(
ptr: *mut bindings::cpufreq_policy_data,
- ) -> kernel::ffi::c_int {
+ ) -> c_int {
from_result(|| {
// SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
// lifetime of `policy`.
@@ -1190,7 +1190,7 @@ impl<T: Driver> Registration<T> {
/// - The pointer arguments must be valid pointers.
unsafe extern "C" fn setpolicy_callback(
ptr: *mut bindings::cpufreq_policy,
- ) -> kernel::ffi::c_int {
+ ) -> c_int {
from_result(|| {
// SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
// lifetime of `policy`.
@@ -1209,7 +1209,7 @@ impl<T: Driver> Registration<T> {
ptr: *mut bindings::cpufreq_policy,
target_freq: c_uint,
relation: c_uint,
- ) -> kernel::ffi::c_int {
+ ) -> c_int {
from_result(|| {
// SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
// lifetime of `policy`.
@@ -1227,7 +1227,7 @@ impl<T: Driver> Registration<T> {
unsafe extern "C" fn target_index_callback(
ptr: *mut bindings::cpufreq_policy,
index: c_uint,
- ) -> kernel::ffi::c_int {
+ ) -> c_int {
from_result(|| {
// SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
// lifetime of `policy`.
@@ -1250,7 +1250,7 @@ impl<T: Driver> Registration<T> {
unsafe extern "C" fn fast_switch_callback(
ptr: *mut bindings::cpufreq_policy,
target_freq: c_uint,
- ) -> kernel::ffi::c_uint {
+ ) -> c_uint {
// SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
// lifetime of `policy`.
let policy = unsafe { Policy::from_raw_mut(ptr) };
@@ -1285,7 +1285,7 @@ impl<T: Driver> Registration<T> {
unsafe extern "C" fn get_intermediate_callback(
ptr: *mut bindings::cpufreq_policy,
index: c_uint,
- ) -> kernel::ffi::c_uint {
+ ) -> c_uint {
// SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
// lifetime of `policy`.
let policy = unsafe { Policy::from_raw_mut(ptr) };
@@ -1306,7 +1306,7 @@ impl<T: Driver> Registration<T> {
unsafe extern "C" fn target_intermediate_callback(
ptr: *mut bindings::cpufreq_policy,
index: c_uint,
- ) -> kernel::ffi::c_int {
+ ) -> c_int {
from_result(|| {
// SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
// lifetime of `policy`.
@@ -1325,7 +1325,7 @@ impl<T: Driver> Registration<T> {
/// # Safety
///
/// - This function may only be called from the cpufreq C infrastructure.
- unsafe extern "C" fn get_callback(cpu: c_uint) -> kernel::ffi::c_uint {
+ unsafe extern "C" fn get_callback(cpu: c_uint) -> c_uint {
// SAFETY: The C API guarantees that `cpu` refers to a valid CPU number.
let cpu_id = unsafe { CpuId::from_u32_unchecked(cpu) };

@@ -1351,7 +1351,7 @@ impl<T: Driver> Registration<T> {
///
/// - This function may only be called from the cpufreq C infrastructure.
/// - The pointer arguments must be valid pointers.
- unsafe extern "C" fn bios_limit_callback(cpu: c_int, limit: *mut c_uint) -> kernel::ffi::c_int {
+ unsafe extern "C" fn bios_limit_callback(cpu: c_int, limit: *mut c_uint) -> c_int {
// SAFETY: The C API guarantees that `cpu` refers to a valid CPU number.
let cpu_id = unsafe { CpuId::from_i32_unchecked(cpu) };

@@ -1372,7 +1372,7 @@ impl<T: Driver> Registration<T> {
unsafe extern "C" fn set_boost_callback(
ptr: *mut bindings::cpufreq_policy,
state: c_int,
- ) -> kernel::ffi::c_int {
+ ) -> c_int {
from_result(|| {
// SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
// lifetime of `policy`.
--
2.34.1