[RFC 0/2] fix dma_map_sg not to do barriers for each buffer

[adharmap@codeaurora.org (Abhijeet Dharmapurikar)]

Russell King - ARM Linux wrote:
> On Wed, Feb 10, 2010 at 01:27:47PM -0800, Randy Dunlap wrote:
>> On 02/10/10 12:37, adharmap at codeaurora.org wrote:
>>> From: Abhijeet Dharmapurikar <adharmap@quicinc.com>
>>>
>>> Please refer to the post here
>>> http://lkml.org/lkml/2010/1/4/347
>>>
>>> These changes are to introduce barrierless dma_map_area and dma_unmap_area and
>>> use them to map the buffers in the scatterlist. For the last buffer, call
>>> the normal dma_map_area(aka with barriers) effectively executing the barrier
>>> at the end of the operation.
>>>
>>> Note that the barrierless operations are implemented for few arm
>>> architectures only and I would implement for others once these are okayed by the
>>> community.
>> So when you add these interfaces for other architectures, you will also
>> update Documentation/DMA-API.txt,  right??
> 
> Do we need barrier-less interfaces for anything other than the dma_*_sg
> functions?

I think, dma_*_sg are the only ones that could benefit from barrier-less 
interfaces.

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