Re: [PATCH] Input: Optimize input_to_handler and input_pass_values function

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Tue, Dec 30, 2014 at 11:19:53AM +0530, anshul.g@samsung.com wrote:
> From: Anshul Garg <anshul.g@samsung.com>
> 
> As input_pass_values function is called everytime when EV_SYN is sent from
> input driver or input event buffer becomes full.
> 
> 1. In case of regular handler, event filter code should not run so added check 
>    whether handler supports filter or not.
> 2. If input device doesn't support EV_KEY event type avoid running auto repeat code.

Can you please split it in 2 patches?

> 
> Signed-off-by: Anshul Garg <anshul.g@samsung.com>
> ---
>  drivers/input/input.c |   37 +++++++++++++++++++++----------------
>  1 file changed, 21 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/input/input.c b/drivers/input/input.c
> index bbec2dc..9d6609b 100644
> --- a/drivers/input/input.c
> +++ b/drivers/input/input.c
> @@ -100,23 +100,24 @@ static unsigned int input_to_handler(struct input_handle *handle,
>  	struct input_value *end = vals;
>  	struct input_value *v;
>  
> -	for (v = vals; v != vals + count; v++) {
> -		if (handler->filter &&
> -		    handler->filter(handle, v->type, v->code, v->value))
> -			continue;
> -		if (end != v)
> -			*end = *v;
> -		end++;
> +	if (handler->filter) {
> +		for (v = vals; v != vals + count; v++) {
> +			if (handler->filter(handle, v->type, v->code, v->value))
> +				continue;
> +			if (end != v)
> +				*end = *v;
> +			end++;
> +		}
> +		count = end - vals;
>  	}
>  
> -	count = end - vals;
>  	if (!count)
>  		return 0;
>  
>  	if (handler->events)
>  		handler->events(handle, vals, count);
>  	else if (handler->event)
> -		for (v = vals; v != end; v++)
> +		for (v = vals; v != vals + count; v++)
>  			handler->event(handle, v->type, v->code, v->value);
>  
>  	return count;
> @@ -143,8 +144,10 @@ static void input_pass_values(struct input_dev *dev,
>  		count = input_to_handler(handle, vals, count);
>  	} else {
>  		list_for_each_entry_rcu(handle, &dev->h_list, d_node)
> -			if (handle->open)
> +			if (handle->open && count)
>  				count = input_to_handler(handle, vals, count);
> +			else
> +				break;

This is not correct. You'll stop delivering events at the very first
closed handle, which is not what we want. We need:

			if (handle->open) {
				count = input_to_handler(handle, vals, count);
				if (count == 0)
					break;
			}

>  	}
>  
>  	rcu_read_unlock();
> @@ -152,12 +155,14 @@ static void input_pass_values(struct input_dev *dev,
>  	add_input_randomness(vals->type, vals->code, vals->value);
>  
>  	/* trigger auto repeat for key events */
> -	for (v = vals; v != vals + count; v++) {
> -		if (v->type == EV_KEY && v->value != 2) {
> -			if (v->value)
> -				input_start_autorepeat(dev, v->code);
> -			else
> -				input_stop_autorepeat(dev);
> +	if (test_bit(EV_KEY, dev->evbit)) {

You might want to test for presence of EV_REP as well.

> +		for (v = vals; v != vals + count; v++) {
> +			if (v->type == EV_KEY && v->value != 2) {
> +				if (v->value)
> +					input_start_autorepeat(dev, v->code);
> +				else
> +					input_stop_autorepeat(dev);
> +			}
>  		}
>  	}
>  }
> -- 
> 1.7.9.5
> 

Thanks.

-- 
Dmitry