[PATCH 1/5] rust: sync: move lockdep types to rust/kernel/sync/lockdep.rs
From: Alice Ryhl
Date: Tue Jun 23 2026 - 11:42:59 EST
The lockdep types are currently stored directly in rust/kernel/sync.rs,
but there are starting to be too many of them to keep them in that file.
Thus, move them to a submodule.
For commonly used lockdep logic it's useful to keep re-exports in
kernel::sync, and this also avoids the need to update any users.
Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>
---
rust/kernel/sync.rs | 135 +-----------------------------------------
rust/kernel/sync/lockdep.rs | 139 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 141 insertions(+), 133 deletions(-)
diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
index 993dbf2caa0e..e87a7e339994 100644
--- a/rust/kernel/sync.rs
+++ b/rust/kernel/sync.rs
@@ -5,10 +5,6 @@
//! This module contains the kernel APIs related to synchronisation that have been ported or
//! wrapped for usage by Rust code in the kernel.
-use crate::prelude::*;
-use crate::types::Opaque;
-use pin_init;
-
mod arc;
pub mod aref;
pub mod atomic;
@@ -16,6 +12,7 @@
pub mod completion;
mod condvar;
pub mod lock;
+pub mod lockdep;
mod locked_by;
pub mod poll;
pub mod rcu;
@@ -28,135 +25,7 @@
pub use lock::global::{global_lock, GlobalGuard, GlobalLock, GlobalLockBackend, GlobalLockedBy};
pub use lock::mutex::{new_mutex, Mutex, MutexGuard};
pub use lock::spinlock::{new_spinlock, SpinLock, SpinLockGuard};
+pub use lockdep::{static_lock_class, LockClassKey};
pub use locked_by::LockedBy;
pub use refcount::Refcount;
pub use set_once::SetOnce;
-
-/// Represents a lockdep class.
-///
-/// Wraps the kernel's `struct lock_class_key`.
-#[repr(transparent)]
-#[pin_data(PinnedDrop)]
-pub struct LockClassKey {
- #[pin]
- inner: Opaque<bindings::lock_class_key>,
-}
-
-// SAFETY: Unregistering a lock class key from a different thread than where it was registered is
-// allowed.
-unsafe impl Send for LockClassKey {}
-
-// SAFETY: `bindings::lock_class_key` is designed to be used concurrently from multiple threads and
-// provides its own synchronization.
-unsafe impl Sync for LockClassKey {}
-
-impl LockClassKey {
- /// Initializes a statically allocated lock class key.
- ///
- /// This is usually used indirectly through the [`static_lock_class!`] macro. See its
- /// documentation for more information.
- ///
- /// # Safety
- ///
- /// * Before using the returned value, it must be pinned in a static memory location.
- /// * The destructor must never run on the returned `LockClassKey`.
- pub const unsafe fn new_static() -> Self {
- LockClassKey {
- inner: Opaque::uninit(),
- }
- }
-
- /// Initializes a dynamically allocated lock class key.
- ///
- /// In the common case of using a statically allocated lock class key, the
- /// [`static_lock_class!`] macro should be used instead.
- ///
- /// # Examples
- ///
- /// ```
- /// use kernel::alloc::KBox;
- /// use kernel::types::ForeignOwnable;
- /// use kernel::sync::{LockClassKey, SpinLock};
- /// use pin_init::stack_pin_init;
- ///
- /// let key = KBox::pin_init(LockClassKey::new_dynamic(), GFP_KERNEL)?;
- /// let key_ptr = key.into_foreign();
- ///
- /// {
- /// stack_pin_init!(let num: SpinLock<u32> = SpinLock::new(
- /// 0,
- /// c"my_spinlock",
- /// // SAFETY: `key_ptr` is returned by the above `into_foreign()`, whose
- /// // `from_foreign()` has not yet been called.
- /// unsafe { <Pin<KBox<LockClassKey>> as ForeignOwnable>::borrow(key_ptr) }
- /// ));
- /// }
- ///
- /// // SAFETY: We dropped `num`, the only use of the key, so the result of the previous
- /// // `borrow` has also been dropped. Thus, it's safe to use from_foreign.
- /// unsafe { drop(<Pin<KBox<LockClassKey>> as ForeignOwnable>::from_foreign(key_ptr)) };
- /// # Ok::<(), Error>(())
- /// ```
- pub fn new_dynamic() -> impl PinInit<Self> {
- pin_init!(Self {
- // SAFETY: lockdep_register_key expects an uninitialized block of memory
- inner <- Opaque::ffi_init(|slot| unsafe { bindings::lockdep_register_key(slot) })
- })
- }
-
- /// Returns a raw pointer to the inner C struct.
- ///
- /// It is up to the caller to use the raw pointer correctly.
- pub fn as_ptr(&self) -> *mut bindings::lock_class_key {
- self.inner.get()
- }
-}
-
-#[pinned_drop]
-impl PinnedDrop for LockClassKey {
- fn drop(self: Pin<&mut Self>) {
- // SAFETY: `self.as_ptr()` was registered with lockdep and `self` is pinned, so the address
- // hasn't changed. Thus, it's safe to pass it to unregister.
- unsafe { bindings::lockdep_unregister_key(self.as_ptr()) }
- }
-}
-
-/// Defines a new static lock class and returns a pointer to it.
-///
-/// # Examples
-///
-/// ```
-/// use kernel::sync::{static_lock_class, Arc, SpinLock};
-///
-/// fn new_locked_int() -> Result<Arc<SpinLock<u32>>> {
-/// Arc::pin_init(SpinLock::new(
-/// 42,
-/// c"new_locked_int",
-/// static_lock_class!(),
-/// ), GFP_KERNEL)
-/// }
-/// ```
-#[macro_export]
-macro_rules! static_lock_class {
- () => {{
- static CLASS: $crate::sync::LockClassKey =
- // SAFETY: The returned `LockClassKey` is stored in static memory and we pin it. Drop
- // never runs on a static global.
- unsafe { $crate::sync::LockClassKey::new_static() };
- $crate::prelude::Pin::static_ref(&CLASS)
- }};
-}
-pub use static_lock_class;
-
-/// Returns the given string, if one is provided, otherwise generates one based on the source code
-/// location.
-#[doc(hidden)]
-#[macro_export]
-macro_rules! optional_name {
- () => {
- $crate::c_str!(::core::concat!(::core::file!(), ":", ::core::line!()))
- };
- ($name:literal) => {
- $crate::c_str!($name)
- };
-}
diff --git a/rust/kernel/sync/lockdep.rs b/rust/kernel/sync/lockdep.rs
new file mode 100644
index 000000000000..784821cc2a39
--- /dev/null
+++ b/rust/kernel/sync/lockdep.rs
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Utilities related to lockdep.
+//!
+//! C headers: [`include/linux/lockdep.h`](srctree/include/linux/lockdep.h)
+
+use crate::{
+ prelude::*,
+ types::Opaque, //
+};
+
+/// Represents a lockdep class.
+///
+/// Wraps the kernel's `struct lock_class_key`.
+#[repr(transparent)]
+#[pin_data(PinnedDrop)]
+pub struct LockClassKey {
+ #[pin]
+ inner: Opaque<bindings::lock_class_key>,
+}
+
+// SAFETY: Unregistering a lock class key from a different thread than where it was registered is
+// allowed.
+unsafe impl Send for LockClassKey {}
+
+// SAFETY: `bindings::lock_class_key` is designed to be used concurrently from multiple threads and
+// provides its own synchronization.
+unsafe impl Sync for LockClassKey {}
+
+impl LockClassKey {
+ /// Initializes a statically allocated lock class key.
+ ///
+ /// This is usually used indirectly through the [`static_lock_class!`] macro. See its
+ /// documentation for more information.
+ ///
+ /// # Safety
+ ///
+ /// * Before using the returned value, it must be pinned in a static memory location.
+ /// * The destructor must never run on the returned `LockClassKey`.
+ pub const unsafe fn new_static() -> Self {
+ LockClassKey {
+ inner: Opaque::uninit(),
+ }
+ }
+
+ /// Initializes a dynamically allocated lock class key.
+ ///
+ /// In the common case of using a statically allocated lock class key, the
+ /// [`static_lock_class!`] macro should be used instead.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use kernel::alloc::KBox;
+ /// use kernel::types::ForeignOwnable;
+ /// use kernel::sync::{LockClassKey, SpinLock};
+ /// use pin_init::stack_pin_init;
+ ///
+ /// let key = KBox::pin_init(LockClassKey::new_dynamic(), GFP_KERNEL)?;
+ /// let key_ptr = key.into_foreign();
+ ///
+ /// {
+ /// stack_pin_init!(let num: SpinLock<u32> = SpinLock::new(
+ /// 0,
+ /// c"my_spinlock",
+ /// // SAFETY: `key_ptr` is returned by the above `into_foreign()`, whose
+ /// // `from_foreign()` has not yet been called.
+ /// unsafe { <Pin<KBox<LockClassKey>> as ForeignOwnable>::borrow(key_ptr) }
+ /// ));
+ /// }
+ ///
+ /// // SAFETY: We dropped `num`, the only use of the key, so the result of the previous
+ /// // `borrow` has also been dropped. Thus, it's safe to use from_foreign.
+ /// unsafe { drop(<Pin<KBox<LockClassKey>> as ForeignOwnable>::from_foreign(key_ptr)) };
+ /// # Ok::<(), Error>(())
+ /// ```
+ pub fn new_dynamic() -> impl PinInit<Self> {
+ pin_init!(Self {
+ // SAFETY: lockdep_register_key expects an uninitialized block of memory
+ inner <- Opaque::ffi_init(|slot| unsafe { bindings::lockdep_register_key(slot) })
+ })
+ }
+
+ /// Returns a raw pointer to the inner C struct.
+ ///
+ /// It is up to the caller to use the raw pointer correctly.
+ pub fn as_ptr(&self) -> *mut bindings::lock_class_key {
+ self.inner.get()
+ }
+}
+
+#[pinned_drop]
+impl PinnedDrop for LockClassKey {
+ fn drop(self: Pin<&mut Self>) {
+ // SAFETY: `self.as_ptr()` was registered with lockdep and `self` is pinned, so the address
+ // hasn't changed. Thus, it's safe to pass it to unregister.
+ unsafe { bindings::lockdep_unregister_key(self.as_ptr()) }
+ }
+}
+
+/// Defines a new static lock class and returns a pointer to it.
+///
+/// # Examples
+///
+/// ```
+/// use kernel::sync::{static_lock_class, Arc, SpinLock};
+///
+/// fn new_locked_int() -> Result<Arc<SpinLock<u32>>> {
+/// Arc::pin_init(SpinLock::new(
+/// 42,
+/// c"new_locked_int",
+/// static_lock_class!(),
+/// ), GFP_KERNEL)
+/// }
+/// ```
+#[macro_export]
+macro_rules! static_lock_class {
+ () => {{
+ static CLASS: $crate::sync::LockClassKey =
+ // SAFETY: The returned `LockClassKey` is stored in static memory and we pin it. Drop
+ // never runs on a static global.
+ unsafe { $crate::sync::LockClassKey::new_static() };
+ $crate::prelude::Pin::static_ref(&CLASS)
+ }};
+}
+pub use static_lock_class;
+
+/// Returns the given string, if one is provided, otherwise generates one based on the source code
+/// location.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! optional_name {
+ () => {
+ $crate::c_str!(::core::concat!(::core::file!(), ":", ::core::line!()))
+ };
+ ($name:literal) => {
+ $crate::c_str!($name)
+ };
+}
--
2.55.0.rc0.799.gd6f94ed593-goog