1 files changed, 32 insertions, 8 deletions

diff --git a/rust/kernel/sync/lock.rs b/rust/kernel/sync/lock.rs
index f6c34ca4d819..41dcddac69e2 100644
--- a/rust/kernel/sync/lock.rs
+++ b/rust/kernel/sync/lock.rs
@@ -6,13 +6,21 @@
 //! spinlocks, raw spinlocks) to be provided with minimal effort.
 
 use super::LockClassKey;
-use crate::{init::PinInit, pin_init, str::CStr, types::Opaque, types::ScopeGuard};
-use core::{cell::UnsafeCell, marker::PhantomData, marker::PhantomPinned};
+use crate::{
+    init::PinInit,
+    pin_init,
+    str::CStr,
+    types::{NotThreadSafe, Opaque, ScopeGuard},
+};
+use core::{cell::UnsafeCell, marker::PhantomPinned};
 use macros::pin_data;
 
 pub mod mutex;
 pub mod spinlock;
 
+pub(super) mod global;
+pub use global::{GlobalGuard, GlobalLock, GlobalLockBackend, GlobalLockedBy};
+
 /// The "backend" of a lock.
 ///
 /// It is the actual implementation of the lock, without the need to repeat patterns used in all
@@ -46,7 +54,7 @@ pub unsafe trait Backend {
     /// remain valid for read indefinitely.
     unsafe fn init(
         ptr: *mut Self::State,
-        name: *const core::ffi::c_char,
+        name: *const crate::ffi::c_char,
         key: *mut bindings::lock_class_key,
     );
 
@@ -58,6 +66,13 @@ pub unsafe trait Backend {
     #[must_use]
     unsafe fn lock(ptr: *mut Self::State) -> Self::GuardState;
 
+    /// Tries to acquire the lock.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that [`Backend::init`] has been previously called.
+    unsafe fn try_lock(ptr: *mut Self::State) -> Option<Self::GuardState>;
+
     /// Releases the lock, giving up its ownership.
     ///
     /// # Safety
@@ -128,6 +143,15 @@ impl<T: ?Sized, B: Backend> Lock<T, B> {
         // SAFETY: The lock was just acquired.
         unsafe { Guard::new(self, state) }
     }
+
+    /// Tries to acquire the lock.
+    ///
+    /// Returns a guard that can be used to access the data protected by the lock if successful.
+    pub fn try_lock(&self) -> Option<Guard<'_, T, B>> {
+        // SAFETY: The constructor of the type calls `init`, so the existence of the object proves
+        // that `init` was called.
+        unsafe { B::try_lock(self.state.get()).map(|state| Guard::new(self, state)) }
+    }
 }
 
 /// A lock guard.
@@ -139,7 +163,7 @@ impl<T: ?Sized, B: Backend> Lock<T, B> {
 pub struct Guard<'a, T: ?Sized, B: Backend> {
     pub(crate) lock: &'a Lock<T, B>,
     pub(crate) state: B::GuardState,
-    _not_send: PhantomData<*mut ()>,
+    _not_send: NotThreadSafe,
 }
 
 // SAFETY: `Guard` is sync when the data protected by the lock is also sync.
@@ -150,9 +174,9 @@ impl<T: ?Sized, B: Backend> Guard<'_, T, B> {
         // SAFETY: The caller owns the lock, so it is safe to unlock it.
         unsafe { B::unlock(self.lock.state.get(), &self.state) };
 
-        // SAFETY: The lock was just unlocked above and is being relocked now.
-        let _relock =
-            ScopeGuard::new(|| unsafe { B::relock(self.lock.state.get(), &mut self.state) });
+        let _relock = ScopeGuard::new(||
+                // SAFETY: The lock was just unlocked above and is being relocked now.
+                unsafe { B::relock(self.lock.state.get(), &mut self.state) });
 
         cb()
     }
@@ -191,7 +215,7 @@ impl<'a, T: ?Sized, B: Backend> Guard<'a, T, B> {
         Self {
             lock,
             state,
-            _not_send: PhantomData,
+            _not_send: NotThreadSafe,
         }
     }
 }