linux-kernel - Re: [PATCH] dmaengine: imx-sdma: Report a DMA_ERROR in status if 'count' or 'dma_address' do not match DMA_SLAVE

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Date:   Thu, 12 Oct 2017 22:33:22 +0530
From:   Vinod Koul <vinod.koul@...el.com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Fabio Estevam <fabio.estevam@....com>,
        Nandor Han <nandor.han@...com>
Cc:     dan.j.williams@...el.com, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] dmaengine: imx-sdma: Report a DMA_ERROR in status if
 'count' or 'dma_address' do not match DMA_SLAVE_BUSWIDTH

On Sun, Sep 24, 2017 at 08:26:41AM +0200, Christophe JAILLET wrote:
> All sanity checks in this function set 'sdmac->status = DMA_ERROR' if
> something looks wrong, except if the byte count or the address don't match
> the bus width.
> 
> Fix it and report the error in status in such a case.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> ---
> Untested, so please review carefuly.
> ---
>  drivers/dma/imx-sdma.c | 17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
> index a67ec1bdc4e0..f0419967eb92 100644
> --- a/drivers/dma/imx-sdma.c
> +++ b/drivers/dma/imx-sdma.c
> @@ -1240,26 +1240,31 @@ static struct dma_async_tx_descriptor *sdma_prep_slave_sg(
>  		sdmac->chn_count += count;
>  
>  		if (sdmac->word_size > DMA_SLAVE_BUSWIDTH_4_BYTES) {
> -			ret =  -EINVAL;
> +			ret = -EINVAL;

this is a style fix and should not be part of this patch

>  			goto err_out;
>  		}
>  
>  		switch (sdmac->word_size) {
>  		case DMA_SLAVE_BUSWIDTH_4_BYTES:
>  			bd->mode.command = 0;
> -			if (count & 3 || sg->dma_address & 3)
> -				return NULL;
> +			if (count & 3 || sg->dma_address & 3) {
> +				ret = -EINVAL;
> +				goto err_out;
> +			}

this looks okay, but then slave configuration comes from different path, so
not sure if not setting was intentional or a miss. Fabio, Nandor??

>  			break;
>  		case DMA_SLAVE_BUSWIDTH_2_BYTES:
>  			bd->mode.command = 2;
> -			if (count & 1 || sg->dma_address & 1)
> -				return NULL;
> +			if (count & 1 || sg->dma_address & 1) {
> +				ret = -EINVAL;
> +				goto err_out;
> +			}
>  			break;
>  		case DMA_SLAVE_BUSWIDTH_1_BYTE:
>  			bd->mode.command = 1;
>  			break;
>  		default:
> -			return NULL;
> +			ret = -EINVAL;
> +			goto err_out;
>  		}
>  
>  		param = BD_DONE | BD_EXTD | BD_CONT;
> -- 
> 2.11.0
> 

-- 
~Vinod