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

[Pavel Machek <pavel@xxxxxx>]

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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