Re: [PATCH v3 12/31] media: entity: Add an iterator helper for connected pads

[Ian Arkver <ian.arkver.dev@gmail.com>]

On 07/03/2019 10:09, Sakari Ailus wrote:
> Hi Jacopo,
> 
> On Tue, Mar 05, 2019 at 07:51:31PM +0100, Jacopo Mondi wrote:
>> From: Sakari Ailus <sakari.ailus@linux.intel.com>
>>
>> Add a helper macro for iterating over pads that are connected through
>> enabled routes. This can be used to find all the connected pads within an
>> entity, for instance starting from the pad which has been obtained during
>> the graph walk.
>>
>> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
>> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
>>
>> - Make __media_entity_next_routed_pad() return NULL and adjust the
>>    iterator to handle that
>> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
>> ---
>>   include/media/media-entity.h | 27 +++++++++++++++++++++++++++
>>   1 file changed, 27 insertions(+)
>>
>> diff --git a/include/media/media-entity.h b/include/media/media-entity.h
>> index 205561545d7e..82f0bdf2a6d1 100644
>> --- a/include/media/media-entity.h
>> +++ b/include/media/media-entity.h
>> @@ -936,6 +936,33 @@ __must_check int media_graph_walk_init(
>>   bool media_entity_has_route(struct media_entity *entity, unsigned int pad0,
>>   			    unsigned int pad1);
>>   
>> +static inline struct media_pad *__media_entity_next_routed_pad(
>> +	struct media_pad *start, struct media_pad *iter)
>> +{
>> +	struct media_entity *entity = start->entity;
>> +
>> +	while (iter < &entity->pads[entity->num_pads] &&
>> +	       !media_entity_has_route(entity, start->index, iter->index))
>> +		iter++;
>> +
>> +	return iter == &entity->pads[entity->num_pads] ? NULL : iter;
> 
> Could you use iter <= ...?
> 
> It doesn't seem to matter here, but it'd seem safer to change the check.
> 

How about something like...

for (; iter < &entity->pads[entity->num_pads]; iter++)
     if (media_entity_has_route(entity, start->index, iter->index))
         return iter;

return NULL;

Regards,
Ian

>> +}
>> +
>> +/**
>> + * media_entity_for_each_routed_pad - Iterate over entity pads connected by routes
>> + *
>> + * @start: The stating pad
>> + * @iter: The iterator pad
>> + *
>> + * Iterate over all pads connected through routes from a given pad
>> + * within an entity. The iteration will include the starting pad itself.
>> + */
>> +#define media_entity_for_each_routed_pad(start, iter)			\
>> +	for (iter = __media_entity_next_routed_pad(			\
>> +		     start, (start)->entity->pads);			\
>> +	     iter != NULL;						\
>> +	     iter = __media_entity_next_routed_pad(start, iter + 1))
>> +
>>   /**
>>    * media_graph_walk_cleanup - Release resources used by graph walk.
>>    *
>