Re: [PATCH v3 4/8] DMA: Freescale: add fsl_dma_free_descriptor() to reduce code duplication

From: Andy Shevchenko
Date: Mon Apr 14 2014 - 09:40:50 EST


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@xxxxxxxxxxxxx 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.

--
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy

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