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Date: Wed, 29 Nov 2017 19:39:27 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Trond Myklebust <trond.myklebust@primarydata.com>,
        Anna Schumaker <Anna.Schumaker@netapp.com>
Subject: Re: [BUILD FAILURE] nfs4state.c fails to compile with gcc 4.5.4
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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.