linux-kernel - Re: [PATCH v1 1/2] dmaengine: fsl-edma: change to guard(mutex) within fsl_edma3

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Date: Fri, 21 Jun 2024 10:48:23 -0400
From: Frank Li <Frank.li@....com>
To: Joy Zou <joy.zou@....com>
Cc: vkoul@...nel.org, imx@...ts.linux.dev, dmaengine@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 1/2] dmaengine: fsl-edma: change to guard(mutex)
 within fsl_edma3_xlate()

On Fri, Jun 21, 2024 at 06:49:31PM +0800, Joy Zou wrote:
> Introduce a scope guard to automatically unlock the mutex within
> fsl_edma3_xlate() to simplify the code.
> 
> Prepare to add source ID checks in the future.
> 
> Signed-off-by: Joy Zou <joy.zou@....com>

Reviewed-by: Frank Li <Frank.Li@....com>

> ---
>  drivers/dma/fsl-edma-main.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/drivers/dma/fsl-edma-main.c b/drivers/dma/fsl-edma-main.c
> index c66185c5a199..d4f29ece69f5 100644
> --- a/drivers/dma/fsl-edma-main.c
> +++ b/drivers/dma/fsl-edma-main.c
> @@ -153,7 +153,7 @@ static struct dma_chan *fsl_edma3_xlate(struct of_phandle_args *dma_spec,
>  
>  	b_chmux = !!(fsl_edma->drvdata->flags & FSL_EDMA_DRV_HAS_CHMUX);
>  
> -	mutex_lock(&fsl_edma->fsl_edma_mutex);
> +	guard(mutex)(&fsl_edma->fsl_edma_mutex);
>  	list_for_each_entry_safe(chan, _chan, &fsl_edma->dma_dev.channels,
>  					device_node) {
>  
> @@ -177,18 +177,15 @@ static struct dma_chan *fsl_edma3_xlate(struct of_phandle_args *dma_spec,
>  		if (!b_chmux && i == dma_spec->args[0]) {
>  			chan = dma_get_slave_channel(chan);
>  			chan->device->privatecnt++;
> -			mutex_unlock(&fsl_edma->fsl_edma_mutex);
>  			return chan;
>  		} else if (b_chmux && !fsl_chan->srcid) {
>  			/* if controller support channel mux, choose a free channel */
>  			chan = dma_get_slave_channel(chan);
>  			chan->device->privatecnt++;
>  			fsl_chan->srcid = dma_spec->args[0];
> -			mutex_unlock(&fsl_edma->fsl_edma_mutex);
>  			return chan;
>  		}
>  	}
> -	mutex_unlock(&fsl_edma->fsl_edma_mutex);
>  	return NULL;
>  }
>  
> -- 
> 2.37.1
>