Re: [GIT] Sparc

From	David Miller <davem@davemloft.net>
Newsgroups	linux.kernel
Subject	Re: [GIT] Sparc
Date	2015-11-06 06:20 +0100
Message-ID	<qrHBn-aP-3@gated-at.bofh.it> (permalink)
References	<qrAzU-3Gs-17@gated-at.bofh.it> <qrDo6-5L5-13@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu, 5 Nov 2015 16:43:52 -0800

> On Thu, Nov 5, 2015 at 1:39 PM, David Miller <davem@davemloft.net> wrote:
>>
>> 5) Fix iommu-common code so it doesn't emit rediculous warnings
>>    on some architectures, particularly ARM.
> 
> Heh. So looking at that patch, I can't but help to react that this:
> 
>   #define IOMMU_ERROR_CODE       (~(unsigned long) 0)
> 
> is still pretty ridiculous.  Maybe just (-1ul), or for those people
> who don't understand C unsigned long arithmetic and think that a
> negative unsigned long looks odd, (~0ul)?

Yeah I struggled with this, believe it or not.

The expression causing the problem was (~(dma_addr_t) 0) (AKA
DMA_ERROR_CODE) being used as the return value.

So I just replicated that expression.  A neuron did fire saying "hey
pinhead, why not just use ~0UL" but I did not listen to the little
voice in my head this time.
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[GIT] Sparc David Miller <davem@davemloft.net> - 2015-11-05 22:50 +0100
  Re: [GIT] Sparc Linus Torvalds <torvalds@linux-foundation.org> - 2015-11-06 01:50 +0100
    Re: [GIT] Sparc Linus Torvalds <torvalds@linux-foundation.org> - 2015-11-06 02:00 +0100
      Re: [GIT] Sparc Julian Calaby <julian.calaby@gmail.com> - 2015-11-06 02:10 +0100
        Re: [GIT] Sparc Julia Lawall <julia.lawall@lip6.fr> - 2015-11-06 07:50 +0100
          Re: [GIT] Sparc Julian Calaby <julian.calaby@gmail.com> - 2015-11-07 04:40 +0100
            Re: [GIT] Sparc Julia Lawall <julia.lawall@lip6.fr> - 2015-11-07 07:10 +0100
      [PATCH] checkpatch: Warn when casting constants to c90 int or  longer types Joe Perches <joe@perches.com> - 2015-11-06 19:40 +0100
    Re: [GIT] Sparc David Miller <davem@davemloft.net> - 2015-11-06 06:20 +0100

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