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References: <20211211063949.49533-1-laoar.shao@gmail.com> <20211211063949.49533-3-laoar.shao@gmail.com>
 <YbWSQy0pmO9RgRUu@qmqm.qmqm.pl>
In-Reply-To: <YbWSQy0pmO9RgRUu@qmqm.qmqm.pl>
From:   Yafang Shao <laoar.shao@gmail.com>
Date:   Mon, 13 Dec 2021 00:26:04 +0800
Message-ID: <CALOAHbA+i96zO+XHOBM+k3F1viOnhe=e=z=Vobc+1Bh8NAP9SA@mail.gmail.com>
Subject: Re: [PATCH -mm v2 2/3] cn_proc: replaced old hard-coded 16 with TASK_COMM_LEN_16
To:     Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Kees Cook <keescook@chromium.org>,
        Petr Mladek <pmladek@suse.com>,
        David Hildenbrand <david@redhat.com>,
        Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>,
        Andrii Nakryiko <andrii.nakryiko@gmail.com>,
        Alexei Starovoitov <alexei.starovoitov@gmail.com>,
        Linux MM <linux-mm@kvack.org>, bpf <bpf@vger.kernel.org>,
        "linux-perf-use." <linux-perf-users@vger.kernel.org>,
        Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Matthew Wilcox <willy@infradead.org>,
        Al Viro <viro@zeniv.linux.org.uk>
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On Sun, Dec 12, 2021 at 2:10 PM Michal Miroslaw <mirq-linux@rere.qmqm.pl> wrote:
>
> On Sat, Dec 11, 2021 at 06:39:48AM +0000, Yafang Shao wrote:
> > This TASK_COMM_LEN_16 has the same meaning with the macro defined in
> > linux/sched.h, but we can't include linux/sched.h in a UAPI header, so
> > we should specifically define it in the cn_proc.h.
> [...]
> > index db210625cee8..6dcccaed383f 100644
> > --- a/include/uapi/linux/cn_proc.h
> > +++ b/include/uapi/linux/cn_proc.h
> > @@ -21,6 +21,8 @@
> >
> >  #include <linux/types.h>
> >
> > +#define TASK_COMM_LEN_16 16
>
> Hi,
>
> Since this is added to UAPI header, maybe you could make it a single
> instance also used elsewhere? Even though this is constant and not
> going to change I don't really like multiplying the sources of truth.
>

Hmm, what about defining it in include/uapi/linux/sched.h ?
Then include "sched.h" in cn_proc.h
And we also define it in tools/include/uapi/linux/sched.h for the
usage in tools.

-- 
Thanks
Yafang