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Subject: Re: [BUILD FAILURE] nfs4state.c fails to compile with gcc 4.5.4
To: Arnd Bergmann <arnd@arndb.de>,
        Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Trond Myklebust <trond.myklebust@primarydata.com>,
        Anna Schumaker <Anna.Schumaker@netapp.com>,
        Christoffer Dall <christoffer.dall@linaro.org>
References: <20171129215853.20172851@vmware.local.home>
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 <CAK8P3a0FYRosxm1pDAKgDHXyyu0z=s1DMUivmdd+U4ttrrVTwA@mail.gmail.com>
From: Marc Zyngier <marc.zyngier@arm.com>
Organization: ARM Ltd
Message-ID: <b47e2478-45d0-96d7-27a9-98f9f2f8d0bf@arm.com>
Date: Thu, 30 Nov 2017 15:55:31 +0000
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On 30/11/17 12:28, Arnd Bergmann wrote:
> On Thu, Nov 30, 2017 at 4:39 AM, Andrew Morton
> <akpm@linux-foundation.org> wrote:
>> On Wed, 29 Nov 2017 19:27:45 -0800 Linus Torvalds <torvalds@linux-foundation.org> wrote:
>>
>>> On Wed, Nov 29, 2017 at 6:58 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
>>>>
>>>> Seems it can't handle the initialization of an anonymous struct within
>>>> an anonymous union.
>>>
>>> I think we've seen this before, and I think there was some trick to
>>> make it work with older gcc versions.
>>>
>>> Maybe the unnamed entry that gets initialized had to be declared
>>> first, and the initializer needed an extra set of braces?
>>>
>>> Something like that.
>>>
>>> But maybe the answer is just to say "4.5.4 is really old".
>>>
>>> Doing some log digging gives me
>>>
>>>     ee9d3429c0e4 ("net/sched/sch_red.c: work around gcc-4.4.4 anon
>>> union initializer issue")
>>>     aa4bf44dc851 ("userns: use union in {g,u}idmap struct")
>>>     6c09ffd02725 ("irqchip/gic-v4: Fix building with ancient gcc")
>>>     c848c49a62b3 ("drivers/media/cec/cec-adap.c: fix build with gcc-4.4.4")
>>>
>>> but they aren't necessarily _exactly_ the same issue.
>>
>> Yeah, I'm the world expert at working around this gcc bug but the nfs4
>> one had me stumped when I looked at it, so I shelved it for revisiting
>> later.
>>
>> It would be nice to fix it, given that this is the only (known) site in
>> the kernel which rules out these compiler versions.
> 
> There are more in drivers/irqchip/irq-gic-v4.c and virt/kvm/arm/vgic/, but
> they are not built on x86. I've fixed it before, but it seems to be coming
> back each time a new GIC variant gets added.
> 
> If anyone cares, I can find the remaining patches I have for this and
> send them again.

If you have patches for either GIC or the vgic, I'll happily take them.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...