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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 15 Sep 2010 08:14:49 -0700
Message-ID: <AANLkTikak7E1otZ3Uffiz2hRvOGrPe6kLcDp3tM69QM_@mail.gmail.com>
Subject: Re: [RFC][PATCH] Cross Memory Attach
To: Christopher Yeoh <cyeoh@au1.ibm.com>
Cc: linux-kernel@vger.kernel.org
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On Wed, Sep 15, 2010 at 8:11 AM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> Btw, please just do this as
>
>   if (copy_to)
>      ret = copy_from_user(..);
>   else
>      ret = copy_to_user(..);
>   kunmap(process_pages[i]);
>   if (ret)
>      goto out;

In fact, you might consider passing in a "copy_out" function pointer
rather than that "copy_to" boolean, and rather than that conditional,
just do a

  ret = copy_out(..);

thing. On sane/good architectures, branch target prediction will make
it all work out to the same work in the end, and it certainly looks
simpler and cleaner.

                                  Linus