Message-ID: <52a9f138-45f0-ca05-b67a-d734663984df@efficios.com>
Date:   Mon, 13 Feb 2023 12:46:06 -0500
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Subject: Re: [PATCH v2 7/7] tools/testing/selftests/bpf: replace open-coded 16
 with TASK_COMM_LEN
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To:     Namhyung Kim <namhyung@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>
Cc:     Yafang Shao <laoar.shao@gmail.com>,
        John Stultz <jstultz@google.com>,
        Alexei Starovoitov <alexei.starovoitov@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Network Development <netdev@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>,
        "linux-perf-use." <linux-perf-users@vger.kernel.org>,
        Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
        linux-mm <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        kernel test robot <oliver.sang@intel.com>,
        kbuild test robot <lkp@intel.com>,
        Andrii Nakryiko <andrii@kernel.org>,
        David Hildenbrand <david@redhat.com>,
        Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>,
        Andrii Nakryiko <andrii.nakryiko@gmail.com>,
        Michal Miroslaw <mirq-linux@rere.qmqm.pl>,
        Peter Zijlstra <peterz@infradead.org>,
        Matthew Wilcox <willy@infradead.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Kees Cook <keescook@chromium.org>,
        Petr Mladek <pmladek@suse.com>,
        Kajetan Puchalski <kajetan.puchalski@arm.com>,
        Lukasz Luba <lukasz.luba@arm.com>,
        Qais Yousef <qyousef@google.com>,
        Daniele Di Proietto <ddiproietto@google.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
References: <20211120112738.45980-1-laoar.shao@gmail.com>
 <20211120112738.45980-8-laoar.shao@gmail.com> <Y+QaZtz55LIirsUO@google.com>
 <CAADnVQ+nf8MmRWP+naWwZEKBFOYr7QkZugETgAVfjKcEVxmOtg@mail.gmail.com>
 <CANDhNCo_=Q3pWc7h=ruGyHdRVGpsMKRY=C2AtZgLDwtGzRz8Kw@mail.gmail.com>
 <20230208212858.477cd05e@gandalf.local.home>
 <20230208213343.40ee15a5@gandalf.local.home>
 <20230211140011.4f15a633@gandalf.local.home>
 <CALOAHbAnFHAiMH4QDgS6xN16B31qfhG8tfQ+iioCr9pw3sP=bw@mail.gmail.com>
 <20230211224455.0a4b2914@gandalf.local.home>
 <CAM9d7chx+azdxfNVVtaC_8eM2a57aBFa3hjh0TvjFt-6Xc7r7w@mail.gmail.com>
From:   Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
In-Reply-To: <CAM9d7chx+azdxfNVVtaC_8eM2a57aBFa3hjh0TvjFt-6Xc7r7w@mail.gmail.com>
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On 2023-02-13 12:43, Namhyung Kim wrote:
> Hi Steve,
> 
> On Sat, Feb 11, 2023 at 8:07 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>>
>> On Sun, 12 Feb 2023 11:38:52 +0800
>> Yafang Shao <laoar.shao@gmail.com> wrote:
>>
>>>> Actually, there are cases that this needs to be a number, as b3bc8547d3be6
>>>> ("tracing: Have TRACE_DEFINE_ENUM affect trace event types as well") made
>>>> it update fields as well as the printk fmt.
>>>>
>>>
>>> It seems that TRACE_DEFINE_ENUM(TASK_COMM_LEN) in the trace events
>>> header files would be a better fix.
>>
>> NACK! I much prefer the proper fix that adds the length.
> 
> Can we just have both enum and macro at the same time?
> I guess the enum would fill the BTF and the macro would provide
> backward compatibility.

This is no need to keep the define. The root cause of the issue is 
addressed by this fix:

https://lore.kernel.org/lkml/20230212154620.4d8fe033@gandalf.local.home/

Thanks,

Mathieu

> 
> Thanks,
> Namhyung

-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com