linux-kernel - Re: [PATCH 07/46] dmaengine: omap-dma: use dmaenginem_async_device

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Date:   Fri, 3 Aug 2018 10:47:30 +0300
From:   Peter Ujfalusi <peter.ujfalusi@...com>
To:     Huang Shijie <sjhuang@...vatar.ai>, <vkoul@...nel.org>
CC:     <dmaengine@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <dave.jiang@...el.com>, <radhey.shyam.pandey@...inx.com>,
        <appana.durga.rao@...inx.com>, <jmkrzyszt@...il.com>,
        <gomonovych@...il.com>, <keescook@...omium.org>,
        <horms+renesas@...ge.net.au>, <geert+renesas@...der.be>,
        <shawnguo@...nel.org>, <baoyou.xie@...aro.org>,
        <michal.simek@...inx.com>, <baohua@...nel.org>,
        <ludovic.desroches@...rochip.com>, <linus.walleij@...aro.org>,
        <david.brown@...aro.org>
Subject: Re: [PATCH 07/46] dmaengine: omap-dma: use
 dmaenginem_async_device_register to simplify the code



On 2018-08-03 10:19, Huang Shijie wrote:
> Use dmaenginem_async_device_register to simplify the code:
>    remove dma_async_device_unregister
> 
> Signed-off-by: Huang Shijie <sjhuang@...vatar.ai>
> ---
>  drivers/dma/ti/omap-dma.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c
> index a4a931ddf6f6..085748c6eb67 100644
> --- a/drivers/dma/ti/omap-dma.c
> +++ b/drivers/dma/ti/omap-dma.c
> @@ -1566,7 +1566,7 @@ static int omap_dma_probe(struct platform_device *pdev)
>  		}
>  	}
>  
> -	rc = dma_async_device_register(&od->ddev);
> +	rc = dmaenginem_async_device_register(&od->ddev);

Why it is dmaenginem_async_device_register() and not aligned other
resource managed functions (devm_* dmam_*), like
devm_dma_async_device_register()

and in dmaenginem_async_device_register() what is the 'm' in dmaenginem ?
DMAengine Managed?

>  	if (rc) {
>  		pr_warn("OMAP-DMA: failed to register slave DMA engine device: %d\n",
>  			rc);
> @@ -1584,7 +1584,6 @@ static int omap_dma_probe(struct platform_device *pdev)
>  				of_dma_simple_xlate, &omap_dma_info);
>  		if (rc) {
>  			pr_warn("OMAP-DMA: failed to register DMA controller\n");
> -			dma_async_device_unregister(&od->ddev);
>  			omap_dma_free(od);
>  		}
>  	}
> @@ -1606,8 +1605,6 @@ static int omap_dma_remove(struct platform_device *pdev)
>  	irq = platform_get_irq(pdev, 1);
>  	devm_free_irq(&pdev->dev, irq, od);
>  
> -	dma_async_device_unregister(&od->ddev);
> -

I think this is a bad idea in general.
We need to unregister the dma-device before we clean up and free resources.

>  	if (!od->legacy) {
>  		/* Disable all interrupts */
>  		omap_dma_glbl_write(od, IRQENABLE_L0, 0);
> 

I'm sorry to say, but it is a NACK from me.

- Péter

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