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Subject: Re:
 arch/mips/boot/compressed/../../../../lib/lz4/lz4_decompress.c:510:5:
 warning: no previous prototype for function
 'LZ4_decompress_safe_forceExtDict'
To:     kernel test robot <lkp@intel.com>
References: <202206260948.akgsho1q-lkp@intel.com>
Cc:     llvm@lists.linux.dev, kbuild-all@lists.01.org,
        linux-kernel@vger.kernel.org,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>
From:   Tiezhu Yang <yangtiezhu@loongson.cn>
Message-ID: <5753fd35-9848-0481-3a77-6a9c02e2170d@loongson.cn>
Date:   Mon, 27 Jun 2022 11:12:42 +0800
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On 06/26/2022 09:14 AM, kernel test robot wrote:
> Hi Tiezhu,
>
> First bad commit (maybe != root cause):

Yes, I think the first bad commit is not the root cause.

>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   0840a7914caa14315a3191178a9f72c742477860
> commit: 7e4fd16b38923028b01d3dbadf4ca973d885c53e MIPS: RALINK: Define pci_remap_iospace under CONFIG_PCI_DRIVERS_GENERIC
> date:   4 weeks ago
> config: mips-randconfig-r035-20220626
> compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 42a7ddb428c999229491b0effbb1a4059149fba8)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # install mips cross compiling tool for clang build
>         # apt-get install binutils-mipsel-linux-gnu
>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7e4fd16b38923028b01d3dbadf4ca973d885c53e
>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout 7e4fd16b38923028b01d3dbadf4ca973d885c53e
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@intel.com>
>
> All warnings (new ones prefixed by >>):
>
>    arch/mips/boot/compressed/decompress.c:42:6: warning: no previous prototype for function 'error' [-Wmissing-prototypes]
>    void error(char *x)
>         ^
>    arch/mips/boot/compressed/decompress.c:42:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
>    void error(char *x)
>    ^
>    static
>    In file included from arch/mips/boot/compressed/decompress.c:64:
>    In file included from arch/mips/boot/compressed/../../../../lib/decompress_unlz4.c:10:
>>> arch/mips/boot/compressed/../../../../lib/lz4/lz4_decompress.c:510:5: warning: no previous prototype for function 'LZ4_decompress_safe_forceExtDict' [-Wmissing-prototypes]
>    int LZ4_decompress_safe_forceExtDict(const char *source, char *dest,
>        ^
>    arch/mips/boot/compressed/../../../../lib/lz4/lz4_decompress.c:510:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
>    int LZ4_decompress_safe_forceExtDict(const char *source, char *dest,
>    ^
[...]

I think the following patch can fix the above build warning:

[PATCH] lib: Make LZ4_decompress_safe_forceExtDict() static
https://lore.kernel.org/lkml/1656298965-8698-1-git-send-email-yangtiezhu@loongson.cn/T/#u

Thanks,
Tiezhu