[PATCH v10 1/8] rust: types: add `NotThreadSafe`

[Alice Ryhl]

On Tue, Sep 24, 2024 at 9:45 PM Serge E. Hallyn <serge at hallyn.com> wrote:
>
> On Sun, Sep 15, 2024 at 02:31:27PM +0000, Alice Ryhl wrote:
> > This introduces a new marker type for types that shouldn't be thread
> > safe. By adding a field of this type to a struct, it becomes non-Send
> > and non-Sync, which means that it cannot be accessed in any way from
> > threads other than the one it was created on.
> >
> > This is useful for APIs that require globals such as `current` to remain
> > constant while the value exists.
> >
> > We update two existing users in the Kernel to use this helper:
> >
> >  * `Task::current()` - moving the return type of this value to a
> >    different thread would not be safe as you can no longer be guaranteed
> >    that the `current` pointer remains valid.
> >  * Lock guards. Mutexes and spinlocks should be unlocked on the same
> >    thread as where they were locked, so we enforce this using the Send
> >    trait.
>
> Hi,
>
> this sounds useful, however from kernel side when I think thread-safe,
> I think must not be used across a sleep.  Would something like ThreadLocked
> or LockedToThread make sense?

Hmm, those names seem pretty similar to the current name to me?

Alice