linux-kernel - Re: [PATCH 01/44] kernel: Add support for poweroff handler call chain

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Message-ID: <20141009103143.GA6787@amd>
Date:	Thu, 9 Oct 2014 12:31:43 +0200
From:	Pavel Machek <pavel@....cz>
To:	Guenter Roeck <linux@...ck-us.net>
Cc:	linux-kernel@...r.kernel.org,
	adi-buildroot-devel@...ts.sourceforge.net,
	devel@...verdev.osuosl.org, devicetree@...r.kernel.org,
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	Andrew Morton <akpm@...ux-foundation.org>,
	Heiko Stuebner <heiko@...ech.de>,
	Romain Perier <romain.perier@...il.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>,
	Alexander Graf <agraf@...e.de>,
	Geert Uytterhoeven <geert@...ux-m68k.org>
Subject: Re: [PATCH 01/44] kernel: Add support for poweroff handler call chain

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.
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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