Re: [PATCH v2 2/4] dmaengine: Add STM32 DMA driver

From: M'boumba Cedric Madianga
Date: Wed Oct 14 2015 - 11:41:33 EST


2015-10-14 17:28 GMT+02:00 Daniel Thompson <daniel.thompson@xxxxxxxxxx>:
> On 14/10/15 16:26, M'boumba Cedric Madianga wrote:
>>
>> 2015-10-14 16:24 GMT+02:00 Daniel Thompson <daniel.thompson@xxxxxxxxxx>:
>>>
>>>
>>> Hmnnn...
>>>
>>> The dmaengine framework will WARN_ONCE() if an dmaengine is removed
>>> whilst
>>> it is active and also works hard to ensure dmaengine modules are not
>>> removed
>>> whilst there are active drivers using the framework.
>>>
>>> How do we get into this function whilst there is still an active DMA
>>> channels?
>>
>>
>> For example, when a user try "rmmod stm32-dma" in uart console.
>> It will enter in stm32_dma_remove while there is potentially still active
>> DMA.
>
>
> Check dmaengine.c for yourself but I think in this case the dmaengine
> framework will hold references to the module and prevent the remove from
> taking place.

Yes I did it.
As far I understand, the dmaengine framework will print a warning
message but doesn't stop removing operation if there are some active
clients.

Cedric.
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