On Tue, Jan 11, 2011 at 01:57:23PM +0100, Thomas Gleixner wrote:

static clockid_t clock_get_array_id(const clockid_t id)
{
	if (id >= 0)
	       return id < MAX_CLOCKS ? id : POSIX_INV_CLOCK_ID;

      	if (clock_is_posix_cpu(id))
		return POSIX_CPU_CLOCK_ID;

	return POSIX_INV_CLOCK_ID;
}

static inline int dispatch_clock_getres(const clockid_t id, struct timespec *ts)
{
	struct k_clock *clk = &posix_clocks[clock_get_array_id(id)];

	return clk->clock_getres ? clk->clock_getres(id, ts) : -EINVAL;
}

I would like to take this idea one step further, like so:

static struct k_clock *clockid_to_kclock(const clockid_t id)
{
	if (id >= 0)
		return id < MAX_CLOCKS ?
			&posix_clocks[id] : &posix_clocks[POSIX_INV_CLOCK_ID];
	...
}

SYSCALL( ... , const clockid_t id, struct timespec *ts)
{
	struct k_clock *clk = clockid_to_kclock(id);

	return clk->clock_getres ? clk->clock_getres(id, ts) : -EINVAL;
}

What do you think?

Thanks,

Richard