[PATCH] rust: sync: add accessor for the lock behind a given guard

Alice Ryhl
2025-01-30T11:39:36Z

Binder has some methods where the caller provides a lock guard, and
Binder needs to be able to assert that the guard is associated with the
right lock. To enable this, add an accessor to obtain a reference to the
underlying lock that you can pass to `ptr::eq`.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
rust/kernel/sync/lock.rs | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/rust/kernel/sync/lock.rs b/rust/kernel/sync/lock.rs
index 41dcddac69e2..681d67275b49 100644
--- a/rust/kernel/sync/lock.rs
+++ b/rust/kernel/sync/lock.rs
@@ -169,7 +169,12 @@ pub struct Guard<'a, T: ?Sized, B: Backend> {
// SAFETY: `Guard` is sync when the data protected by the lock is also sync.
unsafe impl<T: Sync + ?Sized, B: Backend> Sync for Guard<'_, T, B> {}

-impl<T: ?Sized, B: Backend> Guard<'_, T, B> {
+impl<'a, T: ?Sized, B: Backend> Guard<'a, T, B> {
+ /// Returns the lock that this guard originates from.
+ pub fn lock(&self) -> &'a Lock<T, B> {
+ self.lock
+ }
+
pub(crate) fn do_unlocked(&mut self, cb: impl FnOnce() -> U) -> U {
// SAFETY: The caller owns the lock, so it is safe to unlock it.
unsafe { B::unlock(self.lock.state.get(), &self.state) };

---
base-commit: ceff0757f5dafb5be5205988171809c877b1d3e3
change-id: 20250130-guard-get-lock-dd5452793d9a

Best regards,
--
Alice Ryhl <aliceryhl@google.com>