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To: linux-kernel@vger.kernel.org
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: File copy system call proposal
Date: 8 Dec 2001 16:19:26 -0800
Organization: Transmeta Corporation, Santa Clara CA
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In-Reply-To: <1007782956.355.2.camel@quinn.rcn.nmt.edu> <9us387$poh$1@cesium.transmeta.com> <1007791439.355.7.camel@quinn.rcn.nmt.edu> <E16Chyk-0000zH-00@starship.berlin>
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Copyright: Copyright 2001 H. Peter Anvin - All Rights Reserved
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Followup to:  <E16Chyk-0000zH-00@starship.berlin>
By author:    Daniel Phillips <phillips@bonn-fries.net>
In newsgroup: linux.dev.kernel
> 
> There's some merit to this idea.  As Peter pointed out, an in-kernel cp isn't 
> needed: mmap+write does the job.  The question is, how to avoid the 
> copy_from_user and double caching of data?
> 

One thing that one could do for an in-kernel copy is to extend
sendfile() to support any kind of file descriptor.  That'd be a very
clean way to do it.

	-hpa
-- 
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
http://www.zytor.com/~hpa/puzzle.txt	<amsp@zytor.com>
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