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Date: Sat, 30 Jun 2007 14:54:06 -0700
From: "Ulrich Drepper" <drepper@gmail.com>
To: "Davide Libenzi" <davidel@xmailserver.org>
Subject: Re: [patch 0/6] sys_indirect RFC - sys_indirect introduction
Cc: "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
       "Andrew Morton" <akpm@linux-foundation.org>,
       "Linus Torvalds" <torvalds@linux-foundation.org>,
       "Ingo Molnar" <mingo@elte.hu>
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On 6/30/07, Davide Libenzi <davidel@xmailserver.org> wrote:
> But, a __get_user(), once you scrap off all the gcc wrapping, is bacially
> a move. That could even be removed, but really I don't see the reason
> since it allows for a cleaner strcture definition in userland.

Don't generalize.  The 4G/4G kernel, for instance, doesn't have this
property.  Who knows what else will come up.  Anyway, two memcpy are
slower than one.


> But this does not allow more than one context to be set at a time, like
> the current implementation does. Ie, the current implementation allow you
> to:

Of course it does.  It just requires an appropriate union element.
I've listed flags and sigset_t as separate union elements since I
cannot think of a place where we need both extensions.  Should there
be one this can easily be changed.