[Lguest] [PATCH 1/2] Export get_user_pages_fast
Andrew Morton
akpm at linux-foundation.org
Thu Jul 31 03:28:17 EST 2008
On Wed, 30 Jul 2008 20:18:45 +0300 Adrian Bunk <bunk at kernel.org> wrote:
> > > The export would still only be available on x86 since no other arch
> > > would define CONFIG_HAVE_GET_USER_PAGES_FAST.
> > >
> >
> > That's presently true in Linus mainline. The powerpc implementation is
> > in -mm, but apprarently needs a bit more work.
>
> I still don't get the advantage of your suggestion.
>
> With the powerpc implementation included your suggestion doesn't change
> the fact that the export is available only on x86 and powerpc, and if a
> driver author mistakenly uses it and only tests it's driver on x86 it
> will still break on architectures other than x86 or powerpc.
On non-CONFIG_HAVE_GET_USER_PAGES_FAST architectures a
get_user_pages_fast() call will in fact call get_user_pages().
On CONFIG_HAVE_GET_USER_PAGES_FAST architectures, get_user_pages_fast()
is a real function. All architectures which implement that function
should export it to modules. Hence it should be exported from within
generic code.
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