From: Andi Kleen <ak@suse.de>
To: Andrew Morton <akpm@osdl.org>
Cc: Joe Korty <joe.korty@ccur.com>,
Inaky Perez-Gonzalez <inaky@linux.intel.com>,
Paul Jackson <pj@sgi.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] bitmap: separate bitmap parsing for user buffer and kernel buffer
Date: 05 Oct 2006 21:57:04 +0200 [thread overview]
Message-ID: <p73odsqzgbz.fsf@verdi.suse.de> (raw)
In-Reply-To: <20061004181003.6dae6065.akpm@osdl.org>
Andrew Morton <akpm@osdl.org> writes:
> On Wed, 4 Oct 2006 17:56:30 -0700
> Reinette Chatre <reinette.chatre@linux.intel.com> wrote:
>
> > + if (is_user) {
> > + if (__get_user(c, buf++))
> > + return -EFAULT;
> > + }
> > + else
> > + c = *buf++;
>
> Is this actually needed? __get_user(kernel_address) works OK and (believe
> it or not, given all the stuff it involves) boils down to a single instruction.
It is needed on lots of architectures that use separate address spaces
like sparc64, m68k, s390 (and on x86 with 4:4 patches)
-Andi
next prev parent reply other threads:[~2006-10-05 19:57 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-05 0:56 Reinette Chatre
2006-10-05 1:10 ` Andrew Morton
2006-10-05 1:33 ` Inaky Perez-Gonzalez
2006-10-05 1:57 ` Andrew Morton
2006-10-05 19:49 ` [PATCH] bitmap: parse kernel and user buffers Reinette Chatre
2006-10-05 21:48 ` [PATCH] bitmap: parse input from " Reinette Chatre
2006-10-05 22:32 ` Inaky Perez-Gonzalez
2006-10-05 1:40 ` [PATCH] bitmap: separate bitmap parsing for user buffer and kernel buffer H. Peter Anvin
2006-10-05 19:57 ` Andi Kleen [this message]
2006-10-05 20:38 ` Andrew Morton
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