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authorWedson Almeida Filho <walmeida@microsoft.com>2023-04-11 02:45:31 -0300
committerMiguel Ojeda <ojeda@kernel.org>2023-04-21 00:35:26 +0200
commit6ea5aa08857a81be7114b3c21d6aa6db0bc95f99 (patch)
tree4850a5cf34b5a14b77ce0801161ab4695410f51c /rust
parentb0cf5d50210df982878df53ab465e4377ea07065 (diff)
rust: sync: introduce `LockClassKey`
It is a wrapper around C's `lock_class_key`, which is used by the synchronisation primitives that are checked with lockdep. This is in preparation for introducing Rust abstractions for these primitives. Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Waiman Long <longman@redhat.com> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20230411054543.21278-1-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'rust')
-rw-r--r--rust/kernel/sync.rs45
1 files changed, 45 insertions, 0 deletions
diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
index 33da23e3076d..541d235ffbeb 100644
--- a/rust/kernel/sync.rs
+++ b/rust/kernel/sync.rs
@@ -5,6 +5,51 @@
//! 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::types::Opaque;
+
mod arc;
pub use arc::{Arc, ArcBorrow, UniqueArc};
+
+/// Represents a lockdep class. It's a wrapper around C's `lock_class_key`.
+#[repr(transparent)]
+pub struct LockClassKey(Opaque<bindings::lock_class_key>);
+
+// 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 {
+ /// Creates a new lock class key.
+ pub const fn new() -> Self {
+ Self(Opaque::uninit())
+ }
+
+ #[allow(dead_code)]
+ pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key {
+ self.0.get()
+ }
+}
+
+/// Defines a new static lock class and returns a pointer to it.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! static_lock_class {
+ () => {{
+ static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+ &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)
+ };
+}