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Date:   Thu, 7 Jan 2021 09:39:32 +0100
From:   Stefano Garzarella <sgarzare@redhat.com>
To:     Daurnimator <quae@daurnimator.com>
Cc:     Jens Axboe <axboe@kernel.dk>,
        Kernel Hardening <kernel-hardening@lists.openwall.com>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        io-uring <io-uring@vger.kernel.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Stefan Hajnoczi <stefanha@redhat.com>,
        Jann Horn <jannh@google.com>, Jeff Moyer <jmoyer@redhat.com>,
        Aleksa Sarai <asarai@suse.de>,
        Sargun Dhillon <sargun@sargun.me>,
        linux-kernel@vger.kernel.org, Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH v6 2/3] io_uring: add IOURING_REGISTER_RESTRICTIONS opcode
Message-ID: <20210107083932.ho6vo5g5hmdohwqt@steredhat>
References: <20200827145831.95189-1-sgarzare@redhat.com>
 <20200827145831.95189-3-sgarzare@redhat.com>
 <CAEnbY+fS8FXVeouOxN3uohTvo7fBi5r7TQCGBZUmG3MGJhBrYg@mail.gmail.com>
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On Mon, Jan 04, 2021 at 01:26:41AM +1100, Daurnimator wrote:
>On Fri, 28 Aug 2020 at 00:59, Stefano Garzarella <sgarzare@redhat.com> wrote:
>> +               __u8 register_op; /* IORING_RESTRICTION_REGISTER_OP */
>
>Can you confirm that this intentionally limited the future range of
>IORING_REGISTER opcodes to 0-255?
>

It was based on io_uring_probe, so we used u8 for opcodes, but we have 
room to extend it in the future.

So, for now, this allow to register restrictions up to 255 
IORING_REGISTER opcode.