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References: <20230307030457.3499834-1-joel@joelfernandes.org> <753b72f5ecd03f94511495a333eb192c5fc42087.camel@perches.com>
In-Reply-To: <753b72f5ecd03f94511495a333eb192c5fc42087.camel@perches.com>
From:   Joel Fernandes <joel@joelfernandes.org>
Date:   Mon, 6 Mar 2023 22:10:39 -0500
Message-ID: <CAEXW_YRYnikDRTQXwrTpTsQ1r-32FRPABj_Viu+X6Qr7EWqh4g@mail.gmail.com>
Subject: Re: [PATCH] checkpatch: Error out if deprecated RCU API used
To:     Joe Perches <joe@perches.com>
Cc:     linux-kernel@vger.kernel.org, Andy Whitcroft <apw@canonical.com>,
        Dwaipayan Ray <dwaipayanray1@gmail.com>,
        Lukas Bulwahn <lukas.bulwahn@gmail.com>,
        "Paul E. McKenney" <paulmck@kernel.org>, RCU <rcu@vger.kernel.org>,
        Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>,
        Jens Axboe <axboe@kernel.dk>,
        Philipp Reisner <philipp.reisner@linbit.com>,
        Bryan Tan <bryantan@vmware.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Eric Dumazet <edumazet@google.com>,
        Bob Pearson <rpearsonhpe@gmail.com>,
        Ariel Levkovich <lariel@nvidia.com>,
        "Theodore Ts'o" <tytso@mit.edu>, Julian Anastasov <ja@ssi.bg>,
        Uladzislau Rezki <urezki@gmail.com>
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On Mon, Mar 6, 2023 at 10:08=E2=80=AFPM Joe Perches <joe@perches.com> wrote=
:
>
> On Tue, 2023-03-07 at 03:04 +0000, Joel Fernandes (Google) wrote:
> > Single-argument kvfree_rcu() usage is being deprecated [1] [2] as it is
> > error-prone. However, till all users are converted, we would like to in=
troduce
> > checkpatch errors for new patches submitted.
> >
> > This patch adds support for the same. Tested with a trial patch.
> >
> > For now, we are only considering usages that don't have compound
> > nesting, for example ignore: kvfree_rcu( (rcu_head_obj), rcu_head_name)=
.
> > This is sufficient as such usages are unlikely.
> >
> > Once all users are converted and we remove the old API, we can also rev=
ert this
> > checkpatch patch then.
>
> I think this should be added to the deprecated_apis hash instead
>
> our %deprecated_apis =3D (
>         "synchronize_rcu_bh"                    =3D> "synchronize_rcu",
>         "synchronize_rcu_bh_expedited"          =3D> "synchronize_rcu_exp=
edited",
>         "call_rcu_bh"                           =3D> "call_rcu",
>         "rcu_barrier_bh"                        =3D> "rcu_barrier",
>         "synchronize_sched"                     =3D> "synchronize_rcu",
>         "synchronize_sched_expedited"           =3D> "synchronize_rcu_exp=
edited",
>         "call_rcu_sched"                        =3D> "call_rcu",
>         "rcu_barrier_sched"                     =3D> "rcu_barrier",
>         "get_state_synchronize_sched"           =3D> "get_state_synchroni=
ze_rcu",
>         "cond_synchronize_sched"                =3D> "cond_synchronize_rc=
u",
>         "kmap"                                  =3D> "kmap_local_page",
>         "kunmap"                                =3D> "kunmap_local",
>         "kmap_atomic"                           =3D> "kmap_local_page",
>         "kunmap_atomic"                         =3D> "kunmap_local",
> );

This is not an API name change though, it is a "number of arguments"
or argument list change. Is there a different way to do it?

thanks,

 - Joel