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References: <20220301231038.530897-1-Jason@zx2c4.com> <20220301231038.530897-2-Jason@zx2c4.com>
 <Yh8Bsk9RSm22Yr8d@owl.dominikbrodowski.net>
In-Reply-To: <Yh8Bsk9RSm22Yr8d@owl.dominikbrodowski.net>
From:   "Jason A. Donenfeld" <Jason@zx2c4.com>
Date:   Wed, 2 Mar 2022 12:42:56 +0100
Message-ID: <CAHmME9rSz-GqvQf9S9fPLUvSwP0iky90bipGj-o94tkAU1QP1g@mail.gmail.com>
Subject: Re: [PATCH 1/3] random: replace custom notifier chain with standard one
To:     Dominik Brodowski <linux@dominikbrodowski.net>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        Netdev <netdev@vger.kernel.org>,
        Alexander Graf <graf@amazon.com>, Jann Horn <jannh@google.com>,
        Greg KH <gregkh@linuxfoundation.org>,
        "Theodore Ts'o" <tytso@mit.edu>
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Hi Dominik,

On Wed, Mar 2, 2022 at 6:35 AM Dominik Brodowski
<linux@dominikbrodowski.net> wrote:
>
> Am Wed, Mar 02, 2022 at 12:10:36AM +0100 schrieb Jason A. Donenfeld:
> >  /*
> >   * Delete a previously registered readiness callback function.
> >   */
> > -void del_random_ready_callback(struct random_ready_callback *rdy)
> > +int unregister_random_ready_notifier(struct notifier_block *nb)
> >  {
> >       unsigned long flags;
> > -     struct module *owner = NULL;
> > -
> > -     spin_lock_irqsave(&random_ready_list_lock, flags);
> > -     if (!list_empty(&rdy->list)) {
> > -             list_del_init(&rdy->list);
> > -             owner = rdy->owner;
> > -     }
> > -     spin_unlock_irqrestore(&random_ready_list_lock, flags);
> > +     int ret;
> >
> > -     module_put(owner);
> > +     spin_lock_irqsave(&random_ready_chain_lock, flags);
> > +     ret = raw_notifier_chain_unregister(&random_ready_chain, nb);
> > +     spin_unlock_irqrestore(&random_ready_chain_lock, flags);
> > +     return ret;
> >  }
> > -EXPORT_SYMBOL(del_random_ready_callback);
>
> That doesn't seem to be used anywhere, so I'd suggest removing this function
> altogether.

I thought about this, but it feels weird to have a registration
function without an unregistration function... No other notifier is
unbalanced like that.

Jason