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Date:   Mon, 13 Sep 2021 12:23:16 +0200
From:   Eugene Syromiatnikov <esyr@redhat.com>
To:     Ondrej Mosnacek <omosnace@redhat.com>
Cc:     Steffen Klassert <steffen.klassert@secunet.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>,
        Antony Antony <antony.antony@secunet.com>,
        Christian Langrock <christian.langrock@secunet.com>,
        Nicolas Dichtel <nicolas.dichtel@6wind.com>,
        SElinux list <selinux@vger.kernel.org>,
        Paul Moore <paul@paul-moore.com>,
        Stephen Smalley <stephen.smalley.work@gmail.com>,
        Eric Paris <eparis@parisplace.org>,
        network dev <netdev@vger.kernel.org>,
        Linux kernel mailing list <linux-kernel@vger.kernel.org>,
        "Dmitry V. Levin" <ldv@strace.io>,
        Linux API <linux-api@vger.kernel.org>
Subject: Re: [PATCH v2] include/uapi/linux/xfrm.h: Fix XFRM_MSG_MAPPING ABI
 breakage
Message-ID: <20210913102316.GA30886@asgard.redhat.com>
References: <20210912122234.GA22469@asgard.redhat.com>
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On Mon, Sep 13, 2021 at 09:16:39AM +0200, Ondrej Mosnacek wrote:
> Perhaps it would be a good idea to put a comment here to make it less
> likely that this repeats in the future. Something like:
> 
> /* IMPORTANT: Only insert new entries right above this line, otherwise
> you break ABI! */

Well, this statement is true for (almost) every UAPI-exposed enum, and
netlink is vast and relies on enums heavily.  I think it is already
mentioned somewhere in the documentation, and in the end it falls on the
shoulders of the maintainers—to pay additional attention to UAPI changes.