1 files changed, 19 insertions, 7 deletions

diff --git a/rust/kernel/revocable.rs b/rust/kernel/revocable.rs
index db4aa46bb121..46768b374656 100644
--- a/rust/kernel/revocable.rs
+++ b/rust/kernel/revocable.rs
@@ -5,6 +5,8 @@
 //! The [`Revocable`] type wraps other types and allows access to them to be revoked. The existence
 //! of a [`RevocableGuard`] ensures that objects remain valid.
 
+use pin_init::Wrapper;
+
 use crate::{bindings, prelude::*, sync::rcu, types::Opaque};
 use core::{
     marker::PhantomData,
@@ -80,11 +82,11 @@ unsafe impl<T: Sync + Send> Sync for Revocable<T> {}
 
 impl<T> Revocable<T> {
     /// Creates a new revocable instance of the given data.
-    pub fn new(data: impl PinInit<T>) -> impl PinInit<Self> {
-        pin_init!(Self {
+    pub fn new<E>(data: impl PinInit<T, E>) -> impl PinInit<Self, E> {
+        try_pin_init!(Self {
             is_available: AtomicBool::new(true),
             data <- Opaque::pin_init(data),
-        })
+        }? E)
     }
 
     /// Tries to access the revocable wrapped object.
@@ -154,8 +156,10 @@ impl<T> Revocable<T> {
     /// # Safety
     ///
     /// Callers must ensure that there are no more concurrent users of the revocable object.
-    unsafe fn revoke_internal<const SYNC: bool>(&self) {
-        if self.is_available.swap(false, Ordering::Relaxed) {
+    unsafe fn revoke_internal<const SYNC: bool>(&self) -> bool {
+        let revoke = self.is_available.swap(false, Ordering::Relaxed);
+
+        if revoke {
             if SYNC {
                 // SAFETY: Just an FFI call, there are no further requirements.
                 unsafe { bindings::synchronize_rcu() };
@@ -165,6 +169,8 @@ impl<T> Revocable<T> {
             // `compare_exchange` above that takes `is_available` from `true` to `false`.
             unsafe { drop_in_place(self.data.get()) };
         }
+
+        revoke
     }
 
     /// Revokes access to and drops the wrapped object.
@@ -172,10 +178,13 @@ impl<T> Revocable<T> {
     /// Access to the object is revoked immediately to new callers of [`Revocable::try_access`],
     /// expecting that there are no concurrent users of the object.
     ///
+    /// Returns `true` if `&self` has been revoked with this call, `false` if it was revoked
+    /// already.
+    ///
     /// # Safety
     ///
     /// Callers must ensure that there are no more concurrent users of the revocable object.
-    pub unsafe fn revoke_nosync(&self) {
+    pub unsafe fn revoke_nosync(&self) -> bool {
         // SAFETY: By the safety requirement of this function, the caller ensures that nobody is
         // accessing the data anymore and hence we don't have to wait for the grace period to
         // finish.
@@ -189,7 +198,10 @@ impl<T> Revocable<T> {
     /// If there are concurrent users of the object (i.e., ones that called
     /// [`Revocable::try_access`] beforehand and still haven't dropped the returned guard), this
     /// function waits for the concurrent access to complete before dropping the wrapped object.
-    pub fn revoke(&self) {
+    ///
+    /// Returns `true` if `&self` has been revoked with this call, `false` if it was revoked
+    /// already.
+    pub fn revoke(&self) -> bool {
         // SAFETY: By passing `true` we ask `revoke_internal` to wait for the grace period to
         // finish.
         unsafe { self.revoke_internal::<true>() }