linux-kernel - Re: [PATCH 3/3] dmaengine: dw-axi-dmac: ignore interrupt if no descriptor

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Date:   Thu, 21 Jul 2022 18:03:51 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     Ben Dooks <ben.dooks@...ive.com>
Cc:     dmaengine@...r.kernel.org, Eugeniy.Paltsev@...opsys.com,
        linux-kernel@...r.kernel.org,
        Sudip Mukherjee <sudip.mukherjee@...ive.com>,
        Jude Onyenegecha <jude.onyenegecha@...ive.com>
Subject: Re: [PATCH 3/3] dmaengine: dw-axi-dmac: ignore interrupt if no
 descriptor

On 08-07-22, 18:01, Ben Dooks wrote:
> If the channel has no descriptor and the interrupt is raised then the
> kernel will OOPS. Check the result of vchan_next_desc() in the handler
> axi_chan_block_xfer_complete() to avoid the error happening.

Applied, thanks

> 
> Signed-off-by: Ben Dooks <ben.dooks@...ive.com>
> ---
>  drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> index d6ef5f49f281..1fedf4376678 100644
> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> @@ -1082,6 +1082,11 @@ static void axi_chan_block_xfer_complete(struct axi_dma_chan *chan)
>  
>  	/* The completed descriptor currently is in the head of vc list */
>  	vd = vchan_next_desc(&chan->vc);
> +	if (!vd) {
> +		dev_err(chan2dev(chan), "BUG: %s, IRQ with no descriptors\n",
> +			axi_chan_name(chan));
> +		goto out;
> +	}
>  
>  	if (chan->cyclic) {
>  		desc = vd_to_axi_desc(vd);
> @@ -1111,6 +1116,7 @@ static void axi_chan_block_xfer_complete(struct axi_dma_chan *chan)
>  		axi_chan_start_first_queued(chan);
>  	}
>  
> +out:
>  	spin_unlock_irqrestore(&chan->vc.lock, flags);
>  }
>  
> -- 
> 2.35.1

-- 
~Vinod