linux-kernel - Re: [PATCH] dmaengine: idxd: Remove unnecessary synchronize_irq() before free

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Message-ID: <YoI2ZRm3irWmqZDg@matsya>
Date:   Mon, 16 May 2022 17:02:53 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     cgel.zte@...il.com
Cc:     dave.jiang@...el.com, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org, Minghao Chi <chi.minghao@....com.cn>,
        Zeal Robot <zealci@....com.cn>
Subject: Re: [PATCH] dmaengine: idxd: Remove unnecessary synchronize_irq()
 before free_irq()

On 13-05-22, 08:16, cgel.zte@...il.com wrote:
> From: Minghao Chi <chi.minghao@....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.
> 
> Reported-by: Zeal Robot <zealci@....com.cn>

where is this report...?

> Signed-off-by: Minghao Chi <chi.minghao@....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
> 

-- 
~Vinod