linux-kernel - Re: [PATCH v2 1/5] locking: Add rwsem_assert_held() and rwsem_assert_held

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Message-ID: <ZSMlFMTuD/5B1U/n@dread.disaster.area>
Date:   Mon, 9 Oct 2023 08:54:28 +1100
From:   Dave Chinner <david@...morbit.com>
To:     "Matthew Wilcox (Oracle)" <willy@...radead.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>, Will Deacon <will@...nel.org>,
        Waiman Long <longman@...hat.com>, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, Chandan Babu R <chandan.babu@...cle.com>,
        "Darrick J . Wong" <djwong@...nel.org>, linux-xfs@...r.kernel.org,
        Mateusz Guzik <mjguzik@...il.com>
Subject: Re: [PATCH v2 1/5] locking: Add rwsem_assert_held() and
 rwsem_assert_held_write()

On Sat, Oct 07, 2023 at 09:35:39PM +0100, Matthew Wilcox (Oracle) wrote:
> Modelled after lockdep_assert_held() and lockdep_assert_held_write(),
> but are always active, even when lockdep is disabled.  Of course, they
> don't test that _this_ thread is the owner, but it's sufficient to catch
> many bugs and doesn't incur the same performance penalty as lockdep.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
> ---
.....
> @@ -169,6 +189,18 @@ static __always_inline int rwsem_is_contended(struct rw_semaphore *sem)
>   * the RT specific variant.
>   */
>  
> +static inline void rwsem_assert_held(const struct rw_semaphore *sem)
> +{
> +	lockdep_assert_held(sem);
> +	__rwsem_assert_held(sem);
> +}

	if (IS_ENABLED(CONFIG_LOCKDEP))
		lockdep_assert_held(sem);
	else
		__rwsem_assert_held(sem);

-Dave.
-- 
Dave Chinner
david@...morbit.com