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Message-ID: <28a8fccb-508c-7a49-a79a-5167da8fba81@gmail.com>
Date:   Fri, 28 Oct 2022 12:19:48 -0700
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Subject: Re: [PATCH] include/uapi/linux/swab: Fix potentially missing
 __always_inline
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From:   Florian Fainelli <f.fainelli@gmail.com>
To:     Nathan Chancellor <nathan@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>
Cc:     linux-kernel@vger.kernel.org,
        =?UTF-8?Q?Petr_Van=c4=9bk?= <arkamar@atlas.cz>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, Justin Stitt <jstitt007@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Denys Vlasenko <dvlasenk@redhat.com>,
        Ingo Molnar <mingo@kernel.org>,
        "open list:CLANG/LLVM BUILD SUPPORT" <llvm@lists.linux.dev>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        "open list:PERFORMANCE EVENTS SUBSYSTEM" 
        <linux-perf-users@vger.kernel.org>, mmayer@broadcom.com,
        Khem Raj <raj.khem@gmail.com>,
        Philippe Ombredanne <pombredanne@nexb.com>,
        Kate Stewart <kstewart@linuxfoundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Thomas Gleixner <tglx@linutronix.de>
References: <20220927215256.528619-1-f.fainelli@gmail.com>
 <YzTMUpd6HbHmZu8f@dev-arch.thelio-3990X>
 <ed9b8268-0128-0486-04a3-54f343afd38b@gmail.com>
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On 10/6/22 13:33, Florian Fainelli wrote:
> Hi Nathan,
> 
> On 9/28/2022 3:36 PM, Nathan Chancellor wrote:
>> Hi Florian,
>>
>> On Tue, Sep 27, 2022 at 02:52:56PM -0700, Florian Fainelli wrote:
>>> From: Matt Redfearn <matt.redfearn@mips.com>
>>>
>>> Commit bc27fb68aaad ("include/uapi/linux/byteorder, swab: force inlining
>>> of some byteswap operations") added __always_inline to swab functions
>>> and commit 283d75737837 ("uapi/linux/stddef.h: Provide 
>>> __always_inline to
>>> userspace headers") added a definition of __always_inline for use in
>>> exported headers when the kernel's compiler.h is not available.
>>>
>>> However, since swab.h does not include stddef.h, if the header soup does
>>> not indirectly include it, the definition of __always_inline is missing,
>>> resulting in a compilation failure, which was observed compiling the
>>> perf tool using exported headers containing this commit:
>>>
>>> In file included from /usr/include/linux/byteorder/little_endian.h:12:0,
>>>                   from /usr/include/asm/byteorder.h:14,
>>>                   from tools/include/uapi/linux/perf_event.h:20,
>>>                   from perf.h:8,
>>>                   from builtin-bench.c:18:
>>> /usr/include/linux/swab.h:160:8: error: unknown type name 
>>> `__always_inline'
>>>   static __always_inline __u16 __swab16p(const __u16 *p)
>>>
>>> Fix this by replacing the inclusion of linux/compiler.h with
>>> linux/stddef.h to ensure that we pick up that definition if required,
>>> without relying on it's indirect inclusion. compiler.h is then included
>>> indirectly, via stddef.h.
>>>
>>> Fixes: 283d75737837 ("uapi/linux/stddef.h: Provide __always_inline to 
>>> userspace headers")
>>> Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
>>> Reviewed-by: Petr Vaněk <arkamar@atlas.cz>
>>> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
>>
>> I took this through my kernel build matrix and did not see any new
>> issues.
>>
>> Tested-by: Nathan Chancellor <nathan@kernel.org>
> 
> Great thanks! Since this is really useful for kernel-headers in 
> toolchains, it would be great to get this picked up. Arnd is this 
> something that would go via your tree?

Arnd, is this a patch you can merge? Thanks
-- 
Florian