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Subject: Re: [PATCH 2/2] compiler.h: Include asm/rwonce.h under ARM64 and
 ALPHA to fix build errors
To:     Yonghong Song <yhs@fb.com>,
        Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Nathan Chancellor <natechancellor@gmail.com>,
        Nick Desaulniers <ndesaulniers@google.com>
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Cc:     linux-sparse@vger.kernel.org, netdev@vger.kernel.org,
        bpf@vger.kernel.org, clang-built-linux@googlegroups.com,
        linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
        Xuefeng Li <lixuefeng@loongson.cn>,
        Sergei Shtylyov <sergei.shtylyov@gmail.com>,
        kernel test robot <lkp@intel.com>
From:   Tiezhu Yang <yangtiezhu@loongson.cn>
Message-ID: <5663510d-2aa5-c1f2-d0c8-5313cc2a4a18@loongson.cn>
Date:   Mon, 18 Jan 2021 17:25:35 +0800
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On 01/14/2021 01:14 AM, Yonghong Song wrote:
> I do not think this fix is correct. x86 does not define its own
> rwonce.h and still compiles fine.
>
> As noted in the above, we have include/asm-generic/rwonce.h.
> Once you do a proper build, you will have rwonce.h in arch
> generated directory like
>
> -bash-4.4$ find . -name rwonce.h
> ./include/asm-generic/rwonce.h
> ./arch/alpha/include/asm/rwonce.h
> ./arch/arm64/include/asm/rwonce.h
> ./arch/x86/include/generated/asm/rwonce.h
>
> for mips, it should generated in 
> arch/mips/include/generated/asm/rwonce.h. Please double check why this 
> does not happen.

Hi Yonghong,

Thank you very much for your reply.
You are right, this patch is meaningless.

I find this build error when make M=samples/bpf after make clean,
so the ./arch/mips/include/generated/asm/rwonce.h is not exist.

After rebuild the kernel, this header file can be found when make
M=samples/bpf due to samples/bpf/Makefile contains $LINUXINCLUDE.

$ find . -name rwonce.h
./include/asm-generic/rwonce.h
./arch/arm64/include/asm/rwonce.h
./arch/mips/include/generated/asm/rwonce.h
./arch/alpha/include/asm/rwonce.h
$ cat ./arch/mips/include/generated/asm/rwonce.h
#include <asm-generic/rwonce.h>


Hi Sergei and kernel test robot,

Thank you for your suggestion and report,
please ignore this patch, sorry for the noise.

Thanks,
Tiezhu