linux-kernel - Re: [PATCH 1/5] lib: introduce call

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 10 Mar 2008 20:48:53 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Akinobu Mita <akinobu.mita@...il.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/5] lib: introduce call_once()

On Mon, 10 Mar 2008 23:57:05 +0900 Akinobu Mita <akinobu.mita@...il.com> wrote:

> call_once() is an utility function which has similar functionality of
> pthread_once().
> 
> +/*
> + * call_once - call the initialization function only once
> + *
> + * @once_control: guarantee that the init_routine will be called only once
> + * @init_routine: initialization function
> + *
> + * The first call to call_once(), with a given once_control, shall call the
> + * init_routine with no arguments and return the value init_routine returned.
> + * If the init_routine returns zero which indicates the initialization
> + * succeeded, subsequent calls of call_once() with the same once_control shall
> + * not call the init_routine and return zero.
> + */
> +
> +static inline int call_once(struct once_control *once_control,
> +			    int (*init_rouine)(void))
> +{
> +	return likely(once_control->done) ? 0
> +			: call_once_slow(once_control, init_rouine);
> +}

I don't believe that this shold be described in terms of an "init_routine". 
This mechanism can be used for things other than initialisation routines.

It is spelled "routine", not "rouine".


Would it not be simpler and more general to do:

#define ONCE()						\
	({						\
		static long flag;			\
							\
		return !test_and_set_bit(0, flag);	\
	})

and then callers can do

	if (ONCE())
		do_something();

?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/