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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Mon, 4 Jul 2022 14:18:15 +0200
Message-ID: <CAK8P3a2XBGtJMB=Z-W56MLREAr3sAYKqDHo3yg=4hJ4T6x+QdQ@mail.gmail.com>
Subject: Re: [PATCH V4 4/4] LoongArch: Enable ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
To:     Huacai Chen <chenhuacai@loongson.cn>
Cc:     Arnd Bergmann <arnd@arndb.de>, Huacai Chen <chenhuacai@kernel.org>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>, loongarch@lists.linux.dev,
        linux-arch <linux-arch@vger.kernel.org>,
        Xuefeng Li <lixuefeng@loongson.cn>,
        Guo Ren <guoren@kernel.org>, Xuerui Wang <kernel@xen0n.name>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linux-MM <linux-mm@kvack.org>,
        "open list:BROADCOM NVRAM DRIVER" <linux-mips@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Feiyang Chen <chenfeiyang@loongson.cn>,
        Muchun Song <songmuchun@bytedance.com>
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On Mon, Jul 4, 2022 at 1:25 PM Huacai Chen <chenhuacai@loongson.cn> wrote:
> To avoid the following build error on LoongArch we should include linux/
> static_key.h in page-flags.h.
>
> In file included from ./include/linux/mmzone.h:22,
> from ./include/linux/gfp.h:6,
> from ./include/linux/mm.h:7,
> from arch/loongarch/kernel/asm-offsets.c:9:
> ./include/linux/page-flags.h:208:1: warning: data definition has no
> type or storage class
> 208 | DECLARE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON,
> | ^~~~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/page-flags.h:208:1: error: type defaults to 'int' in
> declaration of 'DECLARE_STATIC_KEY_MAYBE' [-Werror=implicit-int]
> ./include/linux/page-flags.h:209:26: warning: parameter names (without
> types) in function declaration

I wonder if page_fixed_fake_head() should be moved out of line to avoid
this, it's already nontrivial here, and that would avoid the static key
in a central header.

       Arnd