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SubjectRe: [PATCH 2/2] dma: mv_xor: do not sync the DMA buffer after being deallocated
Dear Lubomir Rintel,

On Thu, 27 Dec 2012 20:23:48 +0100, Lubomir Rintel wrote:

> dma_sync_single_for_cpu(dma_chan->device->dev, dest_dma,
> MV_XOR_TEST_SIZE, DMA_FROM_DEVICE);
> + dma_unmap_single(dma_chan->device->dev, dest_dma, MV_XOR_TEST_SIZE,
> + DMA_FROM_DEVICE);

I would assume that dma_unmap_single() implies a
dma_sync_single_for_cpu() since you're unmapping the DMA buffer. So if
you use dma_unmap_single(), I think you can remove the call to
dma_sync_single_for_cpu().


> dma_sync_single_for_cpu(dma_chan->device->dev, dest_dma,
> PAGE_SIZE, DMA_FROM_DEVICE);
> + dma_unmap_page(dma_chan->device->dev, dest_dma, PAGE_SIZE,
> + DMA_FROM_DEVICE);

Ditto.

Also, the mv_xor_memcpy_self_test() function not only dma_map_single()
the destination buffer, but also the source buffer. So presumably, the
source buffer should also be dma_unmap_single()'d.

And for the mv_xor_xor_self_test() function, multiple source buffers
are dma_map_page()'d, so they should all be dma_unmap_page()'d I guess,
not only the destination buffer.

Does that make sense?

Thanks,

Thomas
--
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com


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