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To: Rub n Gallardo Fructuoso <ruben@trymedia.com>
cc: "Linux-Kernel" <linux-kernel@vger.kernel.org>
Subject: Re: Address translation 
In-Reply-To: Your message of "Tue, 21 Nov 2000 15:41:26 +0100."
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Date: Tue, 21 Nov 2000 12:20:48 -0500
From: Jeff Dike <jdike@karaya.com>
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ruben@trymedia.com said:
> Does anybody know a function or method in order to translate an user
> space pointer into a valid pointer in kernel mode?

> 	I'd like to avoid copying data (such as the 'copy_to_user' and
> 'copy_from_user' functions do) because it slows down my system. 

The reason that everyone else uses copy_{to,from}_user is that there is no way 
to guarantee that the userspace pointer is valid.  That memory may have been 
swapped out.  The copy macros are prepared to fault the memory in.  The rest 
of the kernel is not.

				Jeff


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