Re: [RFC PATCH] ceph: Delete features that are not used in the kernel

[Leon Romanovsky]

On Wed, Aug 19, 2020 at 10:47:38AM +0200, Ilya Dryomov wrote:
> On Wed, Aug 19, 2020 at 9:57 AM Leon Romanovsky <leon@xxxxxxxxxx> wrote:
> >
> > From: Leon Romanovsky <leonro@xxxxxxxxxx>
> >
> > 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@xxxxxxxxxx>
> > ---
> > 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, W=1 is our default compilation level for Mellanox RDMA submissions.

>
> Thanks,
>
>                 Ilya