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From:   Linus Torvalds <torvalds@linuxfoundation.org>
Date:   Fri, 10 Dec 2021 10:45:33 -0800
Message-ID: <CAHk-=wgVUBc+9UVYp=uhyqTTw-QTHNrJow1Av+1jB4_Va93m1A@mail.gmail.com>
Subject: Re: [PATCH 2/6] cgroup: Allocate cgroup_file_ctx for kernfs_open_file->priv
To:     Tejun Heo <tj@kernel.org>
Cc:     "Eric W. Biederman" <ebiederm@xmission.com>,
        Michal Koutny <mkoutny@suse.com>, Jens Axboe <axboe@kernel.dk>,
        Kees Cook <keescook@chromium.org>,
        Oleg Nesterov <oleg@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Jim Newsome <jnewsome@torproject.org>,
        Alexey Gladkov <legion@kernel.org>,
        Andy Lutomirski <luto@amacapital.net>,
        Jann Horn <jannh@google.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Security Officers <security@kernel.org>,
        Kernel Team <kernel-team@fb.com>
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On Fri, Dec 10, 2021 at 10:38 AM Tejun Heo <tj@kernel.org> wrote:
>
> It's a bit of bikeshedding but I wanna explicitly denote who at currently
> uses the fields, so how about nested structs w/ embedded iterator?

I don't mind being careful about uses if it makes sense and it's
really statically obvious and never used outside that one file so you
have no non-local cases,,,

Yeah, you export the struct in an internal header file right now, but
I think that is just for the upcoming 'ns' member, not the union
members.

But if it then ever becomes a possible source of confusion and it's
not obvious from the context who uses what, I'd rather use the extra 8
bytes in the allocation.

Ok?

                   Linus