bus dma: a flag/quirk for page zero

Andriy Gapon avg at FreeBSD.org
Wed Jan 11 19:56:53 UTC 2012

on 11/01/2012 19:18 Andriy Gapon said the following:
> Actually, I think that on x86 we don't have to do anything special for any memory
> allocations that we do, including the bounce pages, as the page zero is excluded
> from phys_avail and is not available for normal use.

After some additional thinking there is probably no reason to take advantage of
this fact.  First, it would increase differences with other platforms.  Second,
it would add a hidden dependency.  So it's better to be explicit here.

Andriy Gapon

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