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From:   Ilya Dryomov <idryomov@gmail.com>
Date:   Wed, 19 Aug 2020 10:47:38 +0200
Message-ID: <CAOi1vP-54DybxncMy0tyyy62nsgvQEn0DysbOTpmk_tnxnbv-g@mail.gmail.com>
Subject: Re: [RFC PATCH] ceph: Delete features that are not used in the kernel
To:     Leon Romanovsky <leon@kernel.org>
Cc:     Jeff Layton <jlayton@kernel.org>,
        Leon Romanovsky <leonro@nvidia.com>,
        Ceph Development <ceph-devel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Wed, Aug 19, 2020 at 9:57 AM Leon Romanovsky <leon@kernel.org> wrote:
>
> From: Leon Romanovsky <leonro@nvidia.com>
>
> The ceph_features.h has declaration of features that are not in-use
> in kernel code. This causes to seeing such compilation warnings in
> almost every kernel compilation.
>
> ./include/linux/ceph/ceph_features.h:14:24: warning: 'CEPH_FEATURE_UID' defined but not used [-Wunused-const-variable=]
>    14 |  static const uint64_t CEPH_FEATURE_##name = (1ULL<<bit);  \
>       |                        ^~~~~~~~~~~~~
> ./include/linux/ceph/ceph_features.h:75:1: note: in expansion of macro 'DEFINE_CEPH_FEATURE'
>    75 | DEFINE_CEPH_FEATURE( 0, 1, UID)
>       | ^~~~~~~~~~~~~~~~~~~
>
> The upstream kernel indeed doesn't have any use of them, so delete it.
>
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
> I'm sending this as RFC because probably the patch is wrong, but I
> would like to bring your attention to the existing problem and asking
> for an acceptable solution.

Hi Leon,

Yes, removing unused feature definitions is wrong.  Annotating them
as potentially unused would be much better -- I'll send a patch.

I don't think any of us builds with W=1, so these things don't get
noticed.

Thanks,

                Ilya