Re: [PATCH v6 02/14] rust: hrtimer: introduce hrtimer support

[Andreas Hindborg <a.hindborg@kernel.org>]

"Alice Ryhl" <aliceryhl@google.com> writes:

> On Fri, Jan 10, 2025 at 9:17 PM Andreas Hindborg <a.hindborg@kernel.org> wrote:
>>
>> This patch adds support for intrusive use of the hrtimer system. For now,
>> only one timer can be embedded in a Rust struct.
>>
>> The hrtimer Rust API is based on the intrusive style pattern introduced by
>> the Rust workqueue API.
>>
>> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
>> +/// A timer backed by a C `struct hrtimer`.
>> +///
>> +/// # Invariants
>> +///
>> +/// * `self.timer` is initialized by `bindings::hrtimer_setup`.
>> +#[pin_data]
>> +#[repr(C)]
>> +pub struct HrTimer<U> {
>
> nit: We usually use repr(transparent) instead.

`HrTimer` will have an additional field later in the series, and
`transparent` will not work.

>
>> +    #[pin]
>> +    timer: Opaque<bindings::hrtimer>,
>> +    _t: PhantomData<U>,
>> +}
>> +
>> +// SAFETY: A `HrTimer` can be moved to other threads and used/dropped from there.
>> +unsafe impl<U> Send for HrTimer<U> {}
>> +
>> +// SAFETY: Timer operations are locked on C side, so it is safe to operate on a
>> +// timer from multiple threads
>> +unsafe impl<U> Sync for HrTimer<U> {}
>> +
>> +impl<T> HrTimer<T> {
>
> You are inconsistent with whether the generic parameter is called T or U.

Will fix.


Best regards,
Andreas Hindborg