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Message-ID: <2470523a-3508-e788-8407-d6142487b355@intel.com>
Date:   Fri, 13 May 2022 07:30:35 -0700
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Subject: Re: [PATCH] dmaengine: idxd: Remove unnecessary synchronize_irq()
 before free_irq()
Content-Language: en-US
To:     cgel.zte@gmail.com
Cc:     vkoul@kernel.org, dmaengine@vger.kernel.org,
        linux-kernel@vger.kernel.org, Minghao Chi <chi.minghao@zte.com.cn>,
        Zeal Robot <zealci@zte.com.cn>
References: <20220513081622.1631073-1-chi.minghao@zte.com.cn>
From:   Dave Jiang <dave.jiang@intel.com>
In-Reply-To: <20220513081622.1631073-1-chi.minghao@zte.com.cn>
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On 5/13/2022 1:16 AM, cgel.zte@gmail.com wrote:
> From: Minghao Chi <chi.minghao@zte.com.cn>
>
> Calling synchronize_irq() right before free_irq() is quite useless. On one
> hand the IRQ can easily fire again before free_irq() is entered, on the
> other hand free_irq() itself calls synchronize_irq() internally (in a race
> condition free way) before any state associated with the IRQ is freed.

Fair enough. Thanks.

Acked-by: Dave Jiang <dave.jiang@intel.com>


>
> Reported-by: Zeal Robot <zealci@zte.com.cn>
> Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
> ---
>   drivers/dma/idxd/device.c | 1 -
>   1 file changed, 1 deletion(-)
>
> diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
> index 5363fb9218f2..9dd8e6bb21e6 100644
> --- a/drivers/dma/idxd/device.c
> +++ b/drivers/dma/idxd/device.c
> @@ -1179,7 +1179,6 @@ void idxd_wq_free_irq(struct idxd_wq *wq)
>   	struct idxd_device *idxd = wq->idxd;
>   	struct idxd_irq_entry *ie = &wq->ie;
>   
> -	synchronize_irq(ie->vector);
>   	free_irq(ie->vector, ie);
>   	idxd_flush_pending_descs(ie);
>   	if (idxd->request_int_handles)
> --
> 2.25.1
>
>