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From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: "Niklas Söderlund" <niklas.soderlund+renesas@ragnatech.se>,
	"Benoit Parrot" <bparrot@ti.com>,
	linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH v2 12/30] media: entity: Add an iterator helper for connected pads
Date: Tue, 22 Jan 2019 17:38:48 +0200
Message-ID: <20190122153848.GD11461@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20190122153655.q3p3k2zpxtoug4qe@paasikivi.fi.intel.com>

Hi Sakari,

On Tue, Jan 22, 2019 at 05:36:55PM +0200, Sakari Ailus wrote:
> On Wed, Jan 16, 2019 at 01:24:05AM +0200, Laurent Pinchart wrote:
> > On Fri, Nov 02, 2018 at 12:31:26AM +0100, Niklas Söderlund 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>
> >> ---
> >>  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 9540d2af80f19805..4bb1b568e1ac4795 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_for_routed_pads_next(
> >> +	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;
> > 
> > Returning a pointer past the end of the array is asking for trouble. I
> > think we should return NULL in that case, and adapt the check in
> > media_entity_for_routed_pads() accordingly.
> 
> Well, that pointer never gets used, in a similar manner than simply looping
> over an array. I wouldn't change that --- this function is also integrally
> a part of media_entity_for_each_routed_pad() implementation below.

I know it doesn't get used, but it's still asking for trouble, it will
be easy to use it by mistake. Returning NULL would be clearer.

> >> +}
> >> +
> >> +/**
> >> + * media_entity_for_routed_pads - Iterate over entity pads connected by routes
> >> + *
> >> + * @start: The stating pad
> > 
> > s/stating/starting/
> > 
> >> + * @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_routed_pads(start, iter)			\
> > 
> > Maybe media_entity_for_each_routed_pad() ? Or just
> 
> I'd prefer this one: we have media_entity_ prefix for pretty much
> everything that handles entities.

It's a bit long, but OK.

> > for_each_entity_routed_pad() ?
> > 
> >> +	for (iter = __media_entity_for_routed_pads_next(		\
> > 
> > And how about __media_entity_next_routed_pad() ?
> 
> Yes.
> 
> > 
> >> +		     start, (start)->entity->pads);			\
> >> +	     iter < &(start)->entity->pads[(start)->entity->num_pads];	\
> >> +	     iter = __media_entity_for_routed_pads_next(start, iter + 1))
> >> +
> >>  /**
> >>   * media_graph_walk_cleanup - Release resources used by graph walk.
> >>   *

-- 
Regards,

Laurent Pinchart

  reply index

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-01 23:31 [PATCH v2 00/30] v4l: add support for multiplexed streams Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 01/30] media: entity: Use pad as a starting point for graph walk Niklas Söderlund
2019-01-15 21:43   ` Laurent Pinchart
2018-11-01 23:31 ` [PATCH v2 02/30] media: entity: Use pads instead of entities in the media graph walk stack Niklas Söderlund
2019-01-15 22:03   ` Laurent Pinchart
2019-01-15 22:13     ` Sakari Ailus
2019-01-15 22:07   ` Laurent Pinchart
2018-11-01 23:31 ` [PATCH v2 03/30] media: entity: Walk the graph based on pads Niklas Söderlund
2019-01-15 22:21   ` Laurent Pinchart
     [not found]     ` <20190115223406.mxgzl36cp54gb7nv@kekkonen.localdomain>
2019-01-15 23:28       ` Laurent Pinchart
2019-01-22 14:50         ` Sakari Ailus
2019-02-14 15:15   ` Jacopo Mondi
2018-11-01 23:31 ` [PATCH v2 04/30] v4l: mc: Start walk from a specific pad in use count calculation Niklas Söderlund
2019-01-15 22:24   ` Laurent Pinchart
2019-01-15 22:36     ` Sakari Ailus
2018-11-01 23:31 ` [PATCH v2 05/30] media: entity: Move the pipeline from entity to pads Niklas Söderlund
2019-01-15 22:38   ` Laurent Pinchart
2019-01-15 22:48     ` Sakari Ailus
2019-02-14 15:53   ` Jacopo Mondi
2018-11-01 23:31 ` [PATCH v2 06/30] media: entity: Use pad as the starting point for a pipeline Niklas Söderlund
2019-01-15 22:54   ` Laurent Pinchart
2019-01-22 15:31     ` Sakari Ailus
2019-01-22 15:37       ` Laurent Pinchart
2019-01-22 16:16         ` Sakari Ailus
2018-11-01 23:31 ` [PATCH v2 07/30] media: entity: Add has_route entity operation Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 08/30] media: entity: Add media_has_route() function Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 09/30] media: entity: Swap pads if route is checked from source to sink Niklas Söderlund
2019-01-15 22:57   ` Laurent Pinchart
2019-01-22 15:15     ` Sakari Ailus
2019-01-22 15:20       ` Laurent Pinchart
2019-02-18  9:21         ` Jacopo Mondi
2019-02-22 12:18           ` Laurent Pinchart
2019-03-04 12:35             ` Jacopo Mondi
2019-03-05 20:04               ` Laurent Pinchart
2019-03-06  8:29                 ` Jacopo Mondi
2018-11-01 23:31 ` [PATCH v2 10/30] media: entity: Use routing information during graph traversal Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 11/30] media: entity: Skip link validation for pads to which there is no route to Niklas Söderlund
2019-01-15 23:13   ` Laurent Pinchart
2018-11-01 23:31 ` [PATCH v2 12/30] media: entity: Add an iterator helper for connected pads Niklas Söderlund
2019-01-15 23:24   ` Laurent Pinchart
2019-01-22 15:36     ` Sakari Ailus
2019-01-22 15:38       ` Laurent Pinchart [this message]
2019-01-22 16:21         ` Sakari Ailus
2018-11-01 23:31 ` [PATCH v2 13/30] media: entity: Add only connected pads to the pipeline Niklas Söderlund
2019-01-15 23:33   ` Laurent Pinchart
2018-11-01 23:31 ` [PATCH v2 14/30] media: entity: Add debug information in graph walk route check Niklas Söderlund
2019-01-15 23:35   ` Laurent Pinchart
2019-01-22 15:38     ` Sakari Ailus
2018-11-01 23:31 ` [PATCH v2 15/30] media: entity: Look for indirect routes Niklas Söderlund
2019-01-15 23:41   ` Laurent Pinchart
2019-01-22 15:56     ` Sakari Ailus
2018-11-01 23:31 ` [PATCH v2 16/30] v4l: subdev: Add [GS]_ROUTING subdev ioctls and operations Niklas Söderlund
2019-01-15 23:51   ` Laurent Pinchart
2019-01-22 16:14     ` Sakari Ailus
2019-01-22 17:00       ` Laurent Pinchart
2019-02-21 14:59     ` Jacopo Mondi
2019-02-21 23:49       ` Sakari Ailus
2019-02-22  8:46         ` Jacopo Mondi
2019-02-21 14:39   ` Jacopo Mondi
2019-02-21 22:31     ` Sakari Ailus
2019-02-22  8:40       ` Jacopo Mondi
2019-02-22 11:04         ` Sakari Ailus
2019-02-22 11:17           ` Jacopo Mondi
2019-02-22 11:29             ` Sakari Ailus
2019-02-22 13:37               ` Ian Arkver
2019-02-22 13:50               ` Geert Uytterhoeven
2018-11-01 23:31 ` [PATCH v2 17/30] v4l: subdev: compat: Implement handling for VIDIOC_SUBDEV_[GS]_ROUTING Niklas Söderlund
2019-01-08 10:04   ` Geert Uytterhoeven
2019-01-15 23:53   ` Laurent Pinchart
2019-01-22 15:57     ` Sakari Ailus
2019-02-18 11:21     ` Jacopo Mondi
2019-02-21 23:50       ` Sakari Ailus
2018-11-01 23:31 ` [PATCH v2 18/30] v4l: subdev: Take routing information into account in link validation Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 19/30] v4l: subdev: Improve link format validation debug messages Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 20/30] v4l: mc: Add an S_ROUTING helper function for power state changes Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 21/30] v4l: Add bus type to frame descriptors Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 22/30] v4l: Add CSI-2 bus configuration " Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 23/30] v4l: Add stream to frame descriptor Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 24/30] adv748x: csi2: add translation from pixelcode to CSI-2 datatype Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 25/30] adv748x: csi2: only allow formats on sink pads Niklas Söderlund
2019-02-21 14:18   ` Jacopo Mondi
2018-11-01 23:31 ` [PATCH v2 26/30] adv748x: csi2: describe the multiplexed stream Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 27/30] adv748x: csi2: add internal routing configuration Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 28/30] adv748x: afe: add routing support Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 29/30] rcar-csi2: use frame description information to configure CSI-2 bus Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 30/30] rcar-csi2: expose the subdevice internal routing Niklas Söderlund
2018-11-14 13:10   ` Nikita Yushchenko
2018-11-14 19:45     ` Niklas Söderlund
2018-12-03 22:16 ` [PATCH v2 00/30] v4l: add support for multiplexed streams Sakari Ailus
2018-12-05 22:09   ` Niklas Söderlund

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