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

From: Daniel Thompson
Date: Wed Oct 14 2015 - 11:28:32 EST


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.


Daniel.
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