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Re: [PATCH] dmaengine: pl330: use lock of dma channel in pl330_update

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  Re: [PATCH] dmaengine: pl330: use lock of dma channel in pl330_update Vinod Koul <vinod.koul@intel.com> - 2016-09-09 13:50 +0200
    Re: [PATCH] dmaengine: pl330: use lock of dma channel in pl330_update Hsin-yu Chao <hychao@chromium.org> - 2016-09-09 15:00 +0200

#1479912 — Re: [PATCH] dmaengine: pl330: use lock of dma channel in pl330_update

On Fri, Aug 19, 2016 at 09:03:48PM +0800, Hsin-Yu Chao wrote:
> The content of pl330_thread could be modified in pl330_update
> without protection by the lock from the dma channel who currently
> holding this thread. This could cause bug to the calculation of
> in pl330_tx_status, if the running request has just been done and
> moving to next request while calculating the residual number, an
> invalid number from BUSY descriptor could be added up.
> ---
>  drivers/dma/pl330.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> index 31e9c49..2449cb7 100644
> --- a/drivers/dma/pl330.c
> +++ b/drivers/dma/pl330.c
> @@ -1564,6 +1564,19 @@ static void pl330_dotask(unsigned long data)
>  	return;
>  }
>  
> +static struct dma_pl330_chan *get_dma_channel(struct pl330_dmac *pl330,
> +					      struct pl330_thread *thrd)
> +{
> +	struct dma_pl330_chan *pch;
> +	int i;

empty line here please

-- 
~Vinod

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#1479972

It turns out this patch could cause lock dependency issue.
The other patch "Acquire dmac's spinlock in pl330_tx_status" that I've
uploaded is the correct fix to replace this one.

Thanks,
Hsin-yu

On Fri, Sep 9, 2016 at 7:48 PM, Vinod Koul <vinod.koul@intel.com> wrote:
> On Fri, Aug 19, 2016 at 09:03:48PM +0800, Hsin-Yu Chao wrote:
>> The content of pl330_thread could be modified in pl330_update
>> without protection by the lock from the dma channel who currently
>> holding this thread. This could cause bug to the calculation of
>> in pl330_tx_status, if the running request has just been done and
>> moving to next request while calculating the residual number, an
>> invalid number from BUSY descriptor could be added up.
>> ---
>>  drivers/dma/pl330.c | 19 +++++++++++++++++++
>>  1 file changed, 19 insertions(+)
>>
>> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
>> index 31e9c49..2449cb7 100644
>> --- a/drivers/dma/pl330.c
>> +++ b/drivers/dma/pl330.c
>> @@ -1564,6 +1564,19 @@ static void pl330_dotask(unsigned long data)
>>       return;
>>  }
>>
>> +static struct dma_pl330_chan *get_dma_channel(struct pl330_dmac *pl330,
>> +                                           struct pl330_thread *thrd)
>> +{
>> +     struct dma_pl330_chan *pch;
>> +     int i;
>
> empty line here please
>
> --
> ~Vinod

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