rust: debugfs: Replace the usage of Rust native atomics

Rust native atomics are not allowed to use in kernel due to the mismatch
of memory model with Linux kernel memory model, hence remove the usage
of Rust native atomics in debufs.

Reviewed-by: Matthew Maurer <mmaurer@google.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Tested-by: David Gow <davidgow@google.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251022035324.70785-4-boqun.feng@gmail.com

2 files changed, 8 insertions, 10 deletions

diff --git a/samples/rust/rust_debugfs.rs b/samples/rust/rust_debugfs.rs
index 82b61a15a34b..711faa07bece 100644
--- a/samples/rust/rust_debugfs.rs
+++ b/samples/rust/rust_debugfs.rs
@@ -32,14 +32,12 @@
 //! ```
 
 use core::str::FromStr;
-use core::sync::atomic::AtomicUsize;
-use core::sync::atomic::Ordering;
 use kernel::c_str;
 use kernel::debugfs::{Dir, File};
 use kernel::new_mutex;
 use kernel::prelude::*;
+use kernel::sync::atomic::{Atomic, Relaxed};
 use kernel::sync::Mutex;
-
 use kernel::{acpi, device::Core, of, platform, str::CString, types::ARef};
 
 kernel::module_platform_driver! {
@@ -59,7 +57,7 @@ struct RustDebugFs {
     #[pin]
     _compatible: File<CString>,
     #[pin]
-    counter: File<AtomicUsize>,
+    counter: File<Atomic<usize>>,
     #[pin]
     inner: File<Mutex<Inner>>,
 }
@@ -109,7 +107,7 @@ impl platform::Driver for RustDebugFs {
     ) -> Result<Pin<KBox<Self>>> {
         let result = KBox::try_pin_init(RustDebugFs::new(pdev), GFP_KERNEL)?;
         // We can still mutate fields through the files which are atomic or mutexed:
-        result.counter.store(91, Ordering::Relaxed);
+        result.counter.store(91, Relaxed);
         {
             let mut guard = result.inner.lock();
             guard.x = guard.y;
@@ -120,8 +118,8 @@ impl platform::Driver for RustDebugFs {
 }
 
 impl RustDebugFs {
-    fn build_counter(dir: &Dir) -> impl PinInit<File<AtomicUsize>> + '_ {
-        dir.read_write_file(c_str!("counter"), AtomicUsize::new(0))
+    fn build_counter(dir: &Dir) -> impl PinInit<File<Atomic<usize>>> + '_ {
+        dir.read_write_file(c_str!("counter"), Atomic::<usize>::new(0))
     }
 
     fn build_inner(dir: &Dir) -> impl PinInit<File<Mutex<Inner>>> + '_ {
diff --git a/samples/rust/rust_debugfs_scoped.rs b/samples/rust/rust_debugfs_scoped.rs
index b0c4e76b123e..9f0ec5f24cda 100644
--- a/samples/rust/rust_debugfs_scoped.rs
+++ b/samples/rust/rust_debugfs_scoped.rs
@@ -6,9 +6,9 @@
 //! `Scope::dir` to create a variety of files without the need to separately
 //! track them all.
 
-use core::sync::atomic::AtomicUsize;
 use kernel::debugfs::{Dir, Scope};
 use kernel::prelude::*;
+use kernel::sync::atomic::Atomic;
 use kernel::sync::Mutex;
 use kernel::{c_str, new_mutex, str::CString};
 
@@ -62,7 +62,7 @@ fn create_file_write(
     let file_name = CString::try_from_fmt(fmt!("{name_str}"))?;
     for sub in items {
         nums.push(
-            AtomicUsize::new(sub.parse().map_err(|_| EINVAL)?),
+            Atomic::<usize>::new(sub.parse().map_err(|_| EINVAL)?),
             GFP_KERNEL,
         )?;
     }
@@ -109,7 +109,7 @@ impl ModuleData {
 
 struct DeviceData {
     name: CString,
-    nums: KVec<AtomicUsize>,
+    nums: KVec<Atomic<usize>>,
 }
 
 fn init_control(base_dir: &Dir, dyn_dirs: Dir) -> impl PinInit<Scope<ModuleData>> + '_ {