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

Pavel Machek
2014-10-09T10:31:43Z

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
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