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From:   Wedson Almeida Filho <wedsonaf@gmail.com>
Date:   Tue, 11 Apr 2023 15:05:07 -0300
Message-ID: <CANeycqqM5o_4gj2rT=8yV0NGTRWY=jTA6HT4F2Esho-WAJCPOQ@mail.gmail.com>
Subject: Re: [PATCH v4 04/13] locking/spinlock: introduce spin_lock_init_with_key
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>,
        linux-kernel@vger.kernel.org,
        Wedson Almeida Filho <walmeida@microsoft.com>,
        Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
        Waiman Long <longman@redhat.com>,
        Martin Rodriguez Reboredo <yakoyoku@gmail.com>,
        rust-for-linux@vger.kernel.org
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On Tue, 11 Apr 2023 at 02:46, Wedson Almeida Filho <wedsonaf@gmail.com> wrote:
>
> From: Wedson Almeida Filho <walmeida@microsoft.com>
>
> Rust cannot call C macros, so it has its own macro to create a new lock
> class when a spin lock is initialised. This new function allows Rust
> code to pass the lock class it generates to the C implementation.
>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Waiman Long <longman@redhat.com>
> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
> ---
> v1 -> v2: No changes
> v2 -> v3: No changes
> v3 -> v4: No changes
>
>  include/linux/spinlock.h | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
> index be48f1cb1878..cdc92d095133 100644
> --- a/include/linux/spinlock.h
> +++ b/include/linux/spinlock.h
> @@ -327,12 +327,17 @@ static __always_inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
>
>  #ifdef CONFIG_DEBUG_SPINLOCK
>
> +static inline void spin_lock_init_with_key(spinlock_t *lock, const char *name,
> +                                          struct lock_class_key *key)
> +{
> +       __raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
> +}
> +
>  # define spin_lock_init(lock)                                  \
>  do {                                                           \
>         static struct lock_class_key __key;                     \
>                                                                 \
> -       __raw_spin_lock_init(spinlock_check(lock),              \
> -                            #lock, &__key, LD_WAIT_CONFIG);    \
> +       spin_lock_init_with_key(lock, #lock, &__key);           \
>  } while (0)

Peter, the code above is just factoring out spin lock init when
lockdep is enabled to take a lock class key.

Would you be able to review it?

If it's ok with you, we'd like to carry it through the rust tree
because we have code that depends on it.

Thanks,
-Wedson

>
>  #else
> --
> 2.34.1
>