[RFC] consistent_sync and non L1 cache line aligned buffers

[Darin.Johnson at nokia.com]

> If you think about it, you will see that if you are doing DMA to an
> unaligned buffer, and some other unrelated part of the kernel is
> accessing another part of the cache line, you are in trouble no matter
> what sequence of cache flushes/invalidates/whatever you do.

I sort of assumed this was a given.  I'm used to things like
invalidating just 1514 bytes in a larger buffer, because I know
that it's safe.  However, I can agree with your sentiment, since
the actual reason that I made my invalidate routine safer was
because this was simpler than convincing some other programmers
how to do the right thing :-)

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