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

From: Joe Korty
Date: Wed Oct 04 2006 - 10:56:16 EST


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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