Date: Thu, 9 Oct 2014 08:38:36 -0700
From: Guenter Roeck <linux@roeck-us.net>
To: Pavel Machek <pavel@ucw.cz>
Cc: linux-kernel@vger.kernel.org, adi-buildroot-devel@lists.sourceforge.net,
        devel@driverdev.osuosl.org, devicetree@vger.kernel.org,
        lguest@lists.ozlabs.org, linux-acpi@vger.kernel.org,
        linux-alpha@vger.kernel.org, linux-am33-list@redhat.com,
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        linux-hexagon@vger.kernel.org, linux-m32r-ja@ml.linux-m32r.org,
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        linux-ia64@vger.kernel.org, linux-m68k@vger.kernel.org,
        linux-metag@vger.kernel.org, linux-mips@linux-mips.org,
        linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org,
        linux-sh@vger.kernel.org, xen-devel@lists.xenproject.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Heiko Stuebner <heiko@sntech.de>,
        Romain Perier <romain.perier@gmail.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Len Brown <len.brown@intel.com>, Alexander Graf <agraf@suse.de>,
        Geert Uytterhoeven <geert@linux-m68k.org>
Subject: Re: [PATCH 01/44] kernel: Add support for poweroff handler call chain
Message-ID: <20141009153836.GA31987@roeck-us.net>
References: <1412659726-29957-1-git-send-email-linux@roeck-us.net>
 <1412659726-29957-2-git-send-email-linux@roeck-us.net>
 <20141009103143.GA6787@amd>
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On Thu, Oct 09, 2014 at 12:31:43PM +0200, Pavel Machek wrote:
> Hi!
> 
> > +/**
> > + *	register_poweroff_handler_simple - Register function to be called to power off
> > + *					   the system
> > + *	@handler:	Function to be called to power off the system
> > + *	@priority:	Handler priority. For priority guidelines see
> > + *			register_poweroff_handler.
> > + *
> > + *	This is a simplified version of register_poweroff_handler. It does not
> > + *	take a notifier as argument, but a function pointer. The function
> > + *	registers a poweroff handler with specified priority. Poweroff
> > + *	handlers registered with this function can not be unregistered,
> > + *	and only a single poweroff handler can be installed using it.
> > + *
> > + *	This function must not be called from modules and is therefore
> > + *	not exported.
> > + *
> > + *	Returns -EBUSY if a poweroff handler has already been registered
> > + *	using register_poweroff_handler_simple. Otherwise returns zero,
> > + *	since atomic_notifier_chain_register() currently always returns zero.
> > + */
> > +int register_poweroff_handler_simple(void (*handler)(void), int priority)
> > +{
> > +	char symname[KSYM_NAME_LEN];
> > +
> > +	if (poweroff_handler_data.handler) {
> > +		lookup_symbol_name((unsigned long)poweroff_handler_data.handler,
> > +				   symname);
> > +		pr_warn("Poweroff function already registered (%s)", symname);
> > +		lookup_symbol_name((unsigned long)handler, symname);
> > +		pr_cont(", cannot register %s\n", symname);
> > +		return -EBUSY;
> > +	}
> 
> Dunno, are you maybe overdoing the debugging infrastructure a bit?
> This is not going to happen in production, and if it does happen,
> developer can look the symbol name himself.

On the other side, I don't think it hurts to have that message.
Anyway, I'll use %ps as suggested by Geert.

Guenter
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