linux-kernel - Re: [PATCH] bitmap: bitmap_parse takes a kernel buffer instead of a user buffer

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Date:	Wed, 4 Oct 2006 10:55:24 -0400
From:	Joe Korty <joe.korty@...r.com>
To:	Paul Jackson <pj@....com>
Cc:	akpm@...l.org, reinette.chatre@...ux.intel.com,
	linux-kernel@...r.kernel.org, inaky@...ux.intel.com
Subject: Re: [PATCH] bitmap: bitmap_parse takes a kernel buffer instead of a user buffer

On Wed, Oct 04, 2006 at 07:27:46AM -0700, Paul Jackson wrote:

> Perhaps I should have my coffee first, but I don't see where the
> order in which we wrap these affects the need to impose a crude
> upper limit on what the user can ask for.
> 
> Off hand, I'd expect the kernel version to be the actual implementing
> code, and the user version to be the wrapper and also to impose the
> crude upper limit.

I guess I am a sucker for no-transient-buffer (bufferless?)
implementations, as with them there is an intrinsic
simplicity that automatically avoids problems.  The price
in this case, though, is the use of the more expensive
get_user() where, for kernel buffers, it is not needed.

I have no objection though, and in either case we should
impose a sanity check on 'count'.

Joe
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