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Date: Wed, 11 Aug 2010 23:10:43 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Andrew Morton <akpm@linux-foundation.org>
CC: Randy Dunlap <randy.dunlap@oracle.com>, linux-kernel@vger.kernel.org,
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        Linux Arch Mailing List <linux-arch@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: + drivers-acpi-apei-erst-dbgc-get_useru64-doesnt-work-on-i386.patch
 added to -mm tree
References: <201008112336.o7BNaNEj020805@imap1.linux-foundation.org>	<20100811164310.a4790773.randy.dunlap@oracle.com>	<20100811173327.3ae325ff.akpm@linux-foundation.org>	<4C63771B.6030005@zytor.com>	<20100811213013.ab501c6e.akpm@linux-foundation.org>	<4C638140.1080202@zytor.com> <20100811230353.6cb87afd.akpm@linux-foundation.org>
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On 08/11/2010 11:03 PM, Andrew Morton wrote:
> <I suspect you can do get_user() on a 4-byte or 8-byte struct right now
> and it'll work>

Not so:

/home/hpa/kernel/linux-2.6-tip.urgent/arch/x86/lib/testuser.c:12: error: 
conversion to non-scalar type requested

	-hpa

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#include <linux/types.h>
#include <linux/uaccess.h>

struct foo {
	u16 a, b;
};

int bluttan(struct foo *foo)
{
	struct foo bar;

	if (get_user(bar, foo))
		return -1;

	return bar.a + bar.b;
}

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