Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 20 Feb 2019 13:43:45 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     "Kani, Toshi" <toshi.kani@hpe.com>
Cc:     "yuehaibing@huawei.com" <yuehaibing@huawei.com>,
        "cpandya@codeaurora.org" <cpandya@codeaurora.org>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "will.deacon@arm.com" <will.deacon@arm.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "kernel-janitors@vger.kernel.org" <kernel-janitors@vger.kernel.org>
Subject: Re: [PATCH -next] mm: fix set but not used warning
Message-Id: <20190220134345.e39094996c111be4ffa0c976@linux-foundation.org>
In-Reply-To: <7425c8905127ddd078500d4c14a2147bd00422a0.camel@hpe.com>
References: <20190218135743.131904-1-yuehaibing@huawei.com>
        <7425c8905127ddd078500d4c14a2147bd00422a0.camel@hpe.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, 19 Feb 2019 18:28:30 +0000 "Kani, Toshi" <toshi.kani@hpe.com> wrote:

> On Mon, 2019-02-18 at 13:57 +0000, YueHaibing wrote:
> > Fixes gcc '-Wunused-but-set-variable' warning:
> > 
> > lib/ioremap.c: In function 'ioremap_page_range':
> > lib/ioremap.c:203:16: warning:
> >  variable 'start' set but not used [-Wunused-but-set-variable]
> > 
> > flush_cache_vmap may no need param, so add __maybe_unused fix this warning.
> 
> I think flush_cache_vmap should have a proper prototype with
> __maybe_unused for its args.  But, there are so many arch-specific
> definitions at glace, and I am not sure how manageable such change is,
> though...

This is one of the reasons why things like flush_cache_vmap() should
be implemented as static inline C functions, not as macros.