rust: sync: Add MutexGuard type alias

A simple helper alias for code that needs to deal with Guard types returned
from Mutexes.

Signed-off-by: Lyude Paul <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Lyude

rust/kernel/sync.rs

@@ -16,7 +16,7 @@ pub mod poll;
 pub use arc::{Arc, ArcBorrow, UniqueArc};
 pub use condvar::{new_condvar, CondVar, CondVarTimeoutResult};
 pub use lock::global::{global_lock, GlobalGuard, GlobalLock, GlobalLockBackend, GlobalLockedBy};
-pub use lock::mutex::{new_mutex, Mutex};
+pub use lock::mutex::{new_mutex, Mutex, MutexGuard};
 pub use lock::spinlock::{new_spinlock, SpinLock};
 pub use locked_by::LockedBy;
 

rust/kernel/sync/lock/mutex.rs

@@ -86,6 +86,14 @@ pub use new_mutex;
 /// [`struct mutex`]: srctree/include/linux/mutex.h
 pub type Mutex<T> = super::Lock<T, MutexBackend>;
 
+/// A [`Guard`] acquired from locking a [`Mutex`].
+///
+/// This is simply a type alias for a [`Guard`] returned from locking a [`Mutex`]. It will unlock
+/// the [`Mutex`] upon being dropped.
+///
+/// [`Guard`]: super::Guard
+pub type MutexGuard<'a, T> = super::Guard<'a, T, MutexBackend>;
+
 /// A kernel `struct mutex` lock backend.
 pub struct MutexBackend;