Re: [PATCH v6 0/7] rust: add `ww_mutex` support

["Onur Özkan" <work@onurozkan.dev>]

On Thu, 16 Oct 2025 15:47:09 -0400
Lyude Paul <lyude@redhat.com> wrote:

> Hi! One thing I realized I forgot to ask the last time I reviewed
> this: one of the things that seems to be missing is the ability to
> use this API with locks and lock-acquisition mechanisms that already
> exist on the C side of the kernel.
> 
> I think the simplest equivalent to this I can point to is how we have:
> 
>  * Mutex::from_raw() (but only when the type protected by the mutex
> is () )
>  * Guard::from_raw()
> 
> For ww mutexes we should have both of these as well, and also
> ::from_raw() for WwAcquireCtx. This being said - as far as I can
> tell, it doesn't look like it would be a big change for this series
> at all.

Sounds doable, I will make sure to include them in the next version
which I will be working on pretty soon. I couldn't allocate enough time
to work on this due to other priorities.

> 
> Also - thank you for the work so far :)

My pleasure :)

-Onur

> 
> On Wed, 2025-09-03 at 16:13 +0300, Onur Özkan wrote:
> > Changes made in v6:
> >   - Added `unpinned_new` constructor for `WwClass` and updated
> > global macros.
> >   - Changed all tests (and docs) to use Arc/KBox instead of
> > `stack_pin_init` for `WwMutex` and `WwAcquireCtx`.
> >   - Added `LockKind` and `lock_common` helper to unify locking
> > logic.
> >   - Added context-based and context-free locking functions for
> > `WwMutex`.
> >   - Added `ww_mutex/exec` module, a high-level API with auto
> > `EDEADLK` handling mechanism.
> > 
> > Onur Özkan (7):
> >   rust: add C wrappers for ww_mutex inline functions
> >   rust: implement `WwClass` for ww_mutex support
> >   rust: implement `WwMutex`, `WwAcquireCtx` and `WwMutexGuard`
> >   add KUnit coverage on Rust ww_mutex implementation
> >   rust: ww_mutex: add context-free locking functions
> >   rust: ww_mutex/exec: add high-level API
> >   add KUnit coverage on ww_mutex/exec implementation
> > 
> >  rust/helpers/helpers.c                 |   1 +
> >  rust/helpers/ww_mutex.c                |  39 ++
> >  rust/kernel/error.rs                   |   1 +
> >  rust/kernel/sync/lock.rs               |   1 +
> >  rust/kernel/sync/lock/ww_mutex.rs      | 634
> > +++++++++++++++++++++++++ rust/kernel/sync/lock/ww_mutex/exec.rs |
> > 324 +++++++++++++ 6 files changed, 1000 insertions(+)
> >  create mode 100644 rust/helpers/ww_mutex.c
> >  create mode 100644 rust/kernel/sync/lock/ww_mutex.rs
> >  create mode 100644 rust/kernel/sync/lock/ww_mutex/exec.rs
> > 
> > --
> > 2.50.0
>