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Date: Mon, 12 Aug 2002 17:45:30 +1000
From: Rusty Russell <rusty@rustcorp.com.au>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: akpm@zip.com.au, linux-kernel@vger.kernel.org
Subject: Re: [patch 6/12] hold atomic kmaps across generic_file_read
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On Fri, 9 Aug 2002 18:33:09 -0700 (PDT)
Linus Torvalds <torvalds@transmeta.com> wrote:

> 	repeat:
> 		kmap_atomic(..); // this increments preempt count
> 		nr = copy_from_user(..);

Please please please use a different name for "I know I'm not preemptible but
I can handle it" or a flag or something.

That leaves us with the possibility of a BUG() in the "normal" copy_to/from_user
for all those "I'm holding a spinlock while copying to userspace wheeee!" bugs.
Very common mistake for new kernel authors.

With the preempt count we have an easy way of detecting this at runtime: I'd
like to keep that.

Rusty.
-- 
   there are those who do and those who hang on and you don't see too
   many doers quoting their contemporaries.  -- Larry McVoy
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