Date:   Thu, 2 Dec 2021 15:23:36 +0100
From:   Borislav Petkov <bp@alien8.de>
To:     Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc:     X86 ML <x86@kernel.org>,
        Valentin Schneider <valentin.schneider@arm.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Alan Stern <stern@rowland.harvard.edu>,
        Steven Rostedt <rostedt@goodmis.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] notifier: Return an error when a callback has already
 been registered
Message-ID: <YajW6LRVJi2IEHlU@zn.tnic>
References: <20211202133601.23527-1-bp@alien8.de>
 <20211202141630.rdkrtrltxhzdqtyb@linutronix.de>
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In-Reply-To: <20211202141630.rdkrtrltxhzdqtyb@linutronix.de>
Precedence: bulk

On Thu, Dec 02, 2021 at 03:16:30PM +0100, Sebastian Andrzej Siewior wrote:
> >  	while ((*nl) != NULL) {
> > -		if (unlikely((*nl) == n)) {
> > -			WARN(1, "double register detected");
> > -			return 0;
> 
> This could be s/0/-EEXIST/ or do I miss something?

It is...

> I appreciate the updated warning with %ps!

Send peterz your thanks for that. :-)

> > -		}
> > +		if (unlikely((*nl) == n))
> > +			return -EEXIST;
			^^^^^^^^^^^^^^^

... right here.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette