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From: Peter Zijlstra <peterz@infradead.org>
To: Qian Cai <cai@lca.pw>
Cc: mingo@redhat.com, valentin.schneider@arm.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] sched/core: silence a warning in sched_init()
Date: Tue, 25 Jun 2019 17:57:45 +0200	[thread overview]
Message-ID: <20190625155745.GF3419@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1561475229.5154.74.camel@lca.pw>

On Tue, Jun 25, 2019 at 11:07:09AM -0400, Qian Cai wrote:
> On Tue, 2019-06-25 at 16:25 +0200, Peter Zijlstra wrote:
> > On Tue, Jun 25, 2019 at 10:04:19AM -0400, Qian Cai wrote:
> > > On Tue, 2019-06-25 at 15:52 +0200, Peter Zijlstra wrote:
> > > Yes, -Wmissing-prototype makes no sense, but "-Wunused-but-set-variable" is
> > > pretty valid to catch certain developer errors. For example,
> > > 
> > > https://lists.linuxfoundation.org/pipermail/iommu/2019-May/035680.html
> > > 
> > > > 
> > > > As to this one, ideally the compiler would not be stupid, and understand
> > > > the below, but alas.
> > > 
> > > Pretty sure that won't work, as the compiler will complain something like,
> > > 
> > > ISO C90 forbids mixed declarations and code
> > 
> > No, it builds just fine, it's a new block and C allows new variables at
> > every block start -- with the scope of that block.
> 
> I remember I tried that before but recalled the error code wrong. Here it is,
> 
> kernel/sched/core.c:5940:17: warning: unused variable 'ptr' [-Wunused-variable]
>                 unsigned long ptr = (unsigned long)kzalloc(alloc_size,
> GFP_NOWAIT);

Yes, I know, I tried. And GCC is a moron because of it.

  reply	other threads:[~2019-06-25 15:57 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-25 12:44 [PATCH v2] sched/core: silence a warning in sched_init() Qian Cai
2019-06-25 13:52 ` Peter Zijlstra
2019-06-25 14:04   ` Qian Cai
2019-06-25 14:25     ` Peter Zijlstra
2019-06-25 15:07       ` Qian Cai
2019-06-25 15:57         ` Peter Zijlstra [this message]
2019-07-18 20:44           ` Qian Cai
2019-07-08 14:32 ` Qian Cai

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