linux-kernel - Re: [PATCH v3 4/8] DMA: Freescale: add fsl_dma_free

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Date:	Fri, 18 Apr 2014 12:09:30 +0800
From:	Hongbo Zhang <hongbo.zhang@...escale.com>
To:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
CC:	<vkoul@...radead.org>, <dan.j.williams@...el.com>,
	<dmaengine@...r.kernel.org>, <scottwood@...escale.com>,
	<leo.li@...escale.com>, <linuxppc-dev@...ts.ozlabs.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 4/8] DMA: Freescale: add fsl_dma_free_descriptor()
 to reduce code duplication


On 04/14/2014 09:40 PM, Andy Shevchenko wrote:
> On Fri, 2014-04-11 at 16:14 +0800, Hongbo Zhang wrote:
>> On 04/10/2014 07:29 PM, Andy Shevchenko wrote:
>>> On Thu, 2014-04-10 at 15:10 +0800, hongbo.zhang@...escale.com wrote:
> []
>
>>>> @@ -819,8 +826,7 @@ static void fsldma_cleanup_descriptor(struct fsldma_chan *chan,
>>>>    	dma_run_dependencies(txd);
>>>>    
>>>>    	dma_descriptor_unmap(txd);
>>>> -	chan_dbg(chan, "LD %p free\n", desc);
>>>> -	dma_pool_free(chan->desc_pool, desc, txd->phys);
>>>> +	fsl_dma_free_descriptor(chan, desc);
>>> Here is no list_del() call since it's been called in dma_do_tasklet().
>>> What will be the result of double list_del() against the same node?
>> Not clear with your point.
>> This patch is only introducing a common fsl_dma_free_descriptor() to
>> reduce code duplication. And later in the patch 6/8 the
>> fsldma_cleanup_descriptor() is replaced by fsldma_cleanup_descriptorS().
> In the last case you could have a broken kernel which will fails on
> double list_del(). I think it's better to leave this one untouched and
> you may remove it later.
>
> Or move this patch after you have removed that lines.
>

Good catch, thank you Andy.
Yes I prefer to leave this untouched and handle it later.




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