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Date: Wed, 3 Jul 2024 14:41:48 +0200
From: Frederic Weisbecker <frederic@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Valentin Schneider <vschneid@redhat.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC PATCH 1/6] task_work: Provide means to check if a work is
 queued
Message-ID: <ZoVHDHQkGU2ajUCH@localhost.localdomain>
References: <20240625135244.20227-1-frederic@kernel.org>
 <20240625135244.20227-2-frederic@kernel.org>
 <20240625141539.GA14254@redhat.com>
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In-Reply-To: <20240625141539.GA14254@redhat.com>

Le Tue, Jun 25, 2024 at 04:15:39PM +0200, Oleg Nesterov a écrit :
> On 06/25, Frederic Weisbecker wrote:
> >
> > --- a/kernel/task_work.c
> > +++ b/kernel/task_work.c
> > @@ -177,6 +177,7 @@ void task_work_run(void)
> >
> >  		do {
> >  			next = work->next;
> > +			work->next = TASK_WORK_DEQUEUED;
> 
> OK, but then the additional change below makes sense too?
> 
> Oleg.
> ---
> 
> --- x/kernel/task_work.c
> +++ x/kernel/task_work.c
> @@ -106,8 +106,10 @@ task_work_cancel_match(struct task_struc
>  		if (!match(work, data)) {
>  			pprev = &work->next;
>  			work = READ_ONCE(*pprev);
> -		} else if (try_cmpxchg(pprev, &work, work->next))
> +		} else if (try_cmpxchg(pprev, &work, work->next)) {
> +			work->next = TASK_WORK_DEQUEUED;
>  			break;
> +		}
>  	}
>  	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
>  
> 

Yes it does!

Thanks.