Re: [PATCH] [POWERPC] Improve (in|out)_beXX() asm code

Scott Wood
2008-05-20T22:35:31Z

Alan Cox wrote:
>> It looks like we rely on -fno-strict-aliasing to prevent reordering
>> ordinary memory accesses (such as to DMA descriptors) past the I/O
>
> DMA descriptors in main memory are dependant on cache behaviour anyway
> and the dma_* operators should be the ones enforcing the needed behaviour.

What about memory obtained from dma_alloc_coherent()? We still need a
sync and a compiler barrier. The current I/O accessors have the former,
but not the latter.

-Scott