Re: [PATCH] clockevents: Introduce mode specific callbacks

[Peter Zijlstra <peterz@infradead.org>]

On Wed, Feb 04, 2015 at 01:06:23PM +0530, Viresh Kumar wrote:
> +	/*
> +	 * Mode transition callback(s): Only one of the two groups should be
> +	 * defined:
> +	 * - set_mode(), only for modes <= CLOCK_EVT_MODE_RESUME.
> +	 * - set_mode_{shutdown|periodic|oneshot|resume}().
> +	 */
>  	void			(*set_mode)(enum clock_event_mode mode,
>  					    struct clock_event_device *);
> +	int			(*set_mode_periodic)(struct clock_event_device *);
> +	int			(*set_mode_oneshot)(struct clock_event_device *);
> +	int			(*set_mode_shutdown)(struct clock_event_device *);
> +	int			(*set_mode_resume)(struct clock_event_device *);




> +/* Sanity check of mode transition callbacks */
> +static int clockevents_sanity_check(struct clock_event_device *dev)
> +{
> +	/* Legacy set_mode() callback */
> +	if (dev->set_mode)
> +		return 0;
> +
> +	if (dev->features & CLOCK_EVT_FEAT_DUMMY)
> +		return 0;
> +
> +	/* New mode-specific callbacks */
> +	if (!dev->set_mode_shutdown)
> +		return -EINVAL;
> +
> +	if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) &&
> +	    !dev->set_mode_periodic)
> +		return -EINVAL;
> +
> +	if ((dev->features & CLOCK_EVT_FEAT_ONESHOT) &&
> +	    !dev->set_mode_oneshot)
> +		return -EINVAL;
> +
> +	return 0;
> +}

It appears to me you've not actually checked that condition outlined
above, a driver could set both the legacy and the new callbacks.