linux-kernel - Re: [PATCH v2 3/4] DMA: PL330: Balance module remove function with probe

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Date:	Wed, 24 Oct 2012 09:44:51 +0530
From:	Vinod Koul <vkoul@...radead.org>
To:	Inderpal Singh <inderpal.singh@...aro.org>
Cc:	vinod.koul@...el.com, linux-samsung-soc@...r.kernel.org,
	linux-kernel@...r.kernel.org, jassisinghbrar@...il.com,
	boojin.kim@...sung.com, patches@...aro.org, kgene.kim@...sung.com
Subject: Re: [PATCH v2 3/4] DMA: PL330: Balance module remove function with
 probe

On Fri, 2012-10-05 at 15:47 +0530, Inderpal Singh wrote:
> Since peripheral channel resources are not being allocated at probe,
> no need to flush the channels and free the resources in remove function.
> In case, the channel is in use by some client, return EBUSY.
> 
> Signed-off-by: Inderpal Singh <inderpal.singh@...aro.org>
> ---
>  drivers/dma/pl330.c |   13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> index bf71ff7..4b7a34d 100644
> --- a/drivers/dma/pl330.c
> +++ b/drivers/dma/pl330.c
> @@ -3009,18 +3009,21 @@ static int __devexit pl330_remove(struct amba_device *adev)
>  	if (!pdmac)
>  		return 0;
>  
> +	/* check if any client is using any channel */
> +	list_for_each_entry(pch, &pdmac->ddma.channels,
> +			chan.device_node) {
> +
> +		if (pch->chan.client_count)
> +			return -EBUSY;
> +	}
> +
>  	while (!list_empty(&pdmac->desc_pool)) {

Did you get this code executed?
I think No.

The dmaengine holds the reference to channels, so if they are in use and
not freed by client your remove wont be called. So this check is
redundant

-- 
Vinod Koul
Intel Corp.

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