Re: [PATCH 01/17] rust: sync: completion: add wait_for_completion_timeout()

[John Hubbard <jhubbard@nvidia.com>]

On 8/8/26 7:40 PM, Alexandre Courbot wrote:
> On Sat Aug 8, 2026 at 12:11 PM JST, John Hubbard wrote:
>> From: Joel Fernandes <joelagnelf@nvidia.com>
>>
>> A driver that runs an interrupt self-test during probe waits for the
>> handler to fire. wait_for_completion() has no timeout, so a broken
>> interrupt path stalls probe indefinitely. Add a timeout variant of
>> wait_for_completion().
>>
>> Document the type invariant that Completion always holds an initialized
>> struct completion, and cite it in the SAFETY comments.
> 
> That last paragraph (and the associated hunks below) are a different
> thing, and should be its own patch.

OK.

> 
> <...>
>>   /// Synchronization primitive to signal when a certain task has been completed.
>>   ///
>>   /// The [`Completion`] synchronization primitive signals when a certain task has been completed by
>>   /// waking up other tasks that have been queued up to wait for the [`Completion`] to be completed.
>>   ///
>> +/// # Invariants
>> +///
>> +/// `inner` always holds an initialized `struct completion`.
>> +///
>>   /// # Examples
>>   ///
>>   /// ```
>> @@ -96,7 +105,8 @@ fn as_raw(&self) -> *mut bindings::completion {
>>       /// completion is permanently done, i.e. signals all current and future waiters.
>>       #[inline]
>>       pub fn complete_all(&self) {
>> -        // SAFETY: `self.as_raw()` is a pointer to a valid `struct completion`.
>> +        // SAFETY: By the type invariant, `self.as_raw()` is a pointer to an initialized
>> +        // `struct completion`.
>>           unsafe { bindings::complete_all(self.as_raw()) };
>>       }
>>   
>> @@ -108,7 +118,25 @@ pub fn complete_all(&self) {
>>       /// See also [`Completion::complete_all`].
>>       #[inline]
>>       pub fn wait_for_completion(&self) {
>> -        // SAFETY: `self.as_raw()` is a pointer to a valid `struct completion`.
>> +        // SAFETY: By the type invariant, `self.as_raw()` is a pointer to an initialized
>> +        // `struct completion`.
>>           unsafe { bindings::wait_for_completion(self.as_raw()) };
>>       }
> 
> These hunks are what should be extracted, or even dropped as
> `wait_for_completion_timeout` doesn't add any extra requirement for
> them.
OK, I'll just drop those entirely.

thanks,
-- 
John Hubbard