From mboxrd@z Thu Jan  1 00:00:00 1970
From: Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [GIT] Networking
Date: Mon, 2 Nov 2015 13:19:23 -0800
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Cc: David Miller <davem@davemloft.net>,
	Hannes Frederic Sowa <hannes@stressinduktion.org>,
	Andrew Morton <akpm@linux-foundation.org>,
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To: Andy Lutomirski <luto@kernel.org>
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On Mon, Nov 2, 2015 at 1:16 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
> On Mon, Nov 2, 2015 at 12:34 PM, Andy Lutomirski <luto@kernel.org> wrote:
>>
>> Getting overflow checking right in more complicated cases is a PITA.
>
> No it is not. Not for unsigned values.

Just to clarify. The "oevrflow" test for unsigned subtracts  of "a-b"
(it's really an underflow, but whatever) really is just

   (b > a)

Really. That's it. Claiming that that is "complicated" and needs a
helper function is not something sane people do. A fifth-grader that
isn't good at math can understand that.

In contrast, nobody sane understands "usub_overflow(a, b, &res)".

So really. Stop making inane arguments.

                  Linus