From f74cf399e02e24c544b0bd4b1fe8fa2c5ae30b18 Mon Sep 17 00:00:00 2001
From: Boqun Feng <boqun.feng@gmail.com>
Date: Tue, 21 Oct 2025 23:53:24 -0400
Subject: 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
---
 samples/rust/rust_debugfs.rs | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

(limited to 'samples/rust/rust_debugfs.rs')

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>>> + '_ {
-- 
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