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Sender: Tejun Heo <htejun@gmail.com>
Date:   Wed, 10 May 2023 08:34:09 -1000
From:   Tejun Heo <tj@kernel.org>
To:     Johannes Berg <johannes@sipsolutions.net>
Cc:     linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org,
        Lai Jiangshan <jiangshanlai@gmail.com>,
        Johannes Berg <johannes.berg@intel.com>
Subject: Re: [RFC PATCH 2/4] workqueue: support holding a mutex for each work
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References: <20230510160428.175409-1-johannes@sipsolutions.net>
 <20230510175846.cc21c84b0e6b.I9d3df459c43a78530d9c2046724bb45626402d5f@changeid>
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On Wed, May 10, 2023 at 06:04:26PM +0200, Johannes Berg wrote:
> @@ -2387,7 +2389,13 @@ __acquires(&pool->lock)
>  	 */
>  	lockdep_invariant_state(true);
>  	trace_workqueue_execute_start(work);
> -	worker->current_func(work);
> +	if (unlikely(pwq->wq->work_mutex)) {
> +		mutex_lock(pwq->wq->work_mutex);
> +		worker->current_func(work);
> +		mutex_unlock(pwq->wq->work_mutex);
> +	} else {
> +		worker->current_func(work);
> +	}

Ah, I don't know about this. This can't be that difficult to do from the
callee side, right?

Thanks.

-- 
tejun