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From:   Huacai Chen <chenhuacai@kernel.org>
Date:   Thu, 6 Oct 2022 13:25:38 +0800
Message-ID: <CAAhV-H7VPCT3aYeNFeLzLKYW8r3rGnk_X61a1wc-GTROPD2aSg@mail.gmail.com>
Subject: Re: build failure of next-20221005 due to 4078ec1ef5ed ("LoongArch:
 Use TLB for ioremap()")
To:     Xi Ruoyao <xry111@xry111.site>
Cc:     Huacai Chen <chenhuacai@loongson.cn>,
        WANG Xuerui <kernel@xen0n.name>, loongarch@lists.linux.dev,
        linux-kernel@vger.kernel.org, linux-next@vger.kernel.org,
        Sudip Mukherjee <sudipm.mukherjee@gmail.com>
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Hi, Ruoyao,

On Wed, Oct 5, 2022 at 10:14 PM Xi Ruoyao <xry111@xry111.site> wrote:
>
> Hi Huacai,
>
> Try:
>
> #define iounmap(addr) ((void)(addr))
This can solve the problem, and arm use the same way:
#define tlb_flush(tlb)  ((void) tlb)

but I don't know whether this is the correct way.

Huacai

>
> This is how we normally silence an unused variable or parameter warning.
> Not sure if the kernel uses the same convention though.
>
> On Wed, 2022-10-05 at 13:54 +0100, Sudip Mukherjee wrote:
> > On Wed, Oct 5, 2022 at 1:30 PM Huacai Chen <chenhuacai@kernel.org>
> > wrote:
> > >
> > > Hi, Sudip,
> > >
> > > This seems a false positive. When the implementation of iounmap() is
> > > empty (but this is completely legal I think), these drivers will
> > > cause
> > > "unused variable error".
> >
> > And that error will fail the build as allmodconfig will have
> > CONFIG_WERROR=y.
> >
>
> --
> Xi Ruoyao <xry111@xry111.site>
> School of Aerospace Science and Technology, Xidian University
>