Re: [PATCH 06/18] media: v4l: async: Only pass match information for async subdev validation

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sakari,

Thank you for the patch.

On Thu, Mar 30, 2023 at 02:58:41PM +0300, Sakari Ailus wrote:
> Pass only information required for sub-device matching to functions
> checking whether the async sub-device already exists. Do the same for
> debug message printing. This makes further changes to other aspects of
> async sub-devices easier.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>  drivers/media/v4l2-core/v4l2-async.c | 93 ++++++++++++++--------------
>  1 file changed, 46 insertions(+), 47 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> index fc9ae22e2b47..224ebf50f2d0 100644
> --- a/drivers/media/v4l2-core/v4l2-async.c
> +++ b/drivers/media/v4l2-core/v4l2-async.c
> @@ -62,14 +62,14 @@ static void v4l2_async_nf_call_destroy(struct v4l2_async_notifier *n,
>  }
>  
>  static bool match_i2c(struct v4l2_async_notifier *notifier,
> -		      struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
> +		      struct v4l2_subdev *sd, struct v4l2_async_match *match)
>  {
>  #if IS_ENABLED(CONFIG_I2C)
>  	struct i2c_client *client = i2c_verify_client(sd->dev);
>  
>  	return client &&
> -		asd->match.i2c.adapter_id == client->adapter->nr &&
> -		asd->match.i2c.address == client->addr;
> +		match->i2c.adapter_id == client->adapter->nr &&
> +		match->i2c.address == client->addr;
>  #else
>  	return false;
>  #endif
> @@ -84,26 +84,26 @@ static struct device *notifier_dev(struct v4l2_async_notifier *notifier)
>  static bool
>  match_fwnode_one(struct v4l2_async_notifier *notifier,
>  		 struct v4l2_subdev *sd, struct fwnode_handle *sd_fwnode,
> -		 struct v4l2_async_subdev *asd)
> +		 struct v4l2_async_match *match)
>  {
>  	struct fwnode_handle *asd_dev_fwnode;

match_dev_node, to remove references to asd ?

>  	bool ret;
>  
>  	dev_dbg(sd->dev, "async: fwnode match: need %pfw, trying %pfw\n",
> -		sd_fwnode, asd->match.fwnode);
> +		sd_fwnode, match->fwnode);
>  
> -	if (sd_fwnode == asd->match.fwnode) {
> +	if (sd_fwnode == match->fwnode) {
>  		dev_dbg(sd->dev, "async: direct match found\n");
>  		return true;
>  	}
>  
> -	if (!fwnode_graph_is_endpoint(asd->match.fwnode)) {
> +	if (!fwnode_graph_is_endpoint(match->fwnode)) {
>  		dev_dbg(sd->dev,
>  			"async: async subdev fwnode not endpoint, no match\n");

The reference to "subdev" could be dropped here too.

>  		return false;
>  	}
>  
> -	asd_dev_fwnode = fwnode_graph_get_port_parent(asd->match.fwnode);
> +	asd_dev_fwnode = fwnode_graph_get_port_parent(match->fwnode);
>  
>  	ret = sd_fwnode == asd_dev_fwnode;
>  
> @@ -116,12 +116,12 @@ match_fwnode_one(struct v4l2_async_notifier *notifier,
>  }
>  
>  static bool match_fwnode(struct v4l2_async_notifier *notifier,
> -			 struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
> +			 struct v4l2_subdev *sd, struct v4l2_async_match *match)
>  {
>  	dev_dbg(sd->dev, "async: matching for notifier %pfw, sd %pfw\n",
>  		dev_fwnode(notifier_dev(notifier)), sd->fwnode);
>  
> -	if (match_fwnode_one(notifier, sd, sd->fwnode, asd))
> +	if (match_fwnode_one(notifier, sd, sd->fwnode, match))
>  		return true;
>  
>  	/* Also check the secondary fwnode. */
> @@ -130,7 +130,7 @@ static bool match_fwnode(struct v4l2_async_notifier *notifier,
>  
>  	dev_dbg(sd->dev, "async: trying secondary fwnode match\n");
>  
> -	return match_fwnode_one(notifier, sd, sd->fwnode->secondary, asd);
> +	return match_fwnode_one(notifier, sd, sd->fwnode->secondary, match);
>  }
>  
>  static LIST_HEAD(subdev_list);
> @@ -142,7 +142,7 @@ v4l2_async_find_match(struct v4l2_async_notifier *notifier,
>  		      struct v4l2_subdev *sd)
>  {
>  	bool (*match)(struct v4l2_async_notifier *notifier,
> -		      struct v4l2_subdev *sd, struct v4l2_async_subdev *asd);
> +		      struct v4l2_subdev *sd, struct v4l2_async_match *match);
>  	struct v4l2_async_subdev *asd;
>  
>  	list_for_each_entry(asd, &notifier->waiting, list) {
> @@ -161,7 +161,7 @@ v4l2_async_find_match(struct v4l2_async_notifier *notifier,
>  		}
>  
>  		/* match cannot be NULL here */
> -		if (match(notifier, sd, asd))
> +		if (match(notifier, sd, &asd->match))
>  			return asd;
>  	}
>  
> @@ -169,20 +169,18 @@ v4l2_async_find_match(struct v4l2_async_notifier *notifier,
>  }
>  
>  /* Compare two async sub-device descriptors for equivalence */
> -static bool asd_equal(struct v4l2_async_subdev *asd_x,
> -		      struct v4l2_async_subdev *asd_y)
> +static bool asd_equal(struct v4l2_async_match *match1,
> +		      struct v4l2_async_match *match2)

The function doesn't deal with asds anymore, let's rename it.
v4l2_async_match_equal() could be a good name. Please also update the
comment above the function.

>  {
> -	if (asd_x->match.type != asd_y->match.type)
> +	if (match1->type != match2->type)
>  		return false;
>  
> -	switch (asd_x->match.type) {
> +	switch (match1->type) {
>  	case V4L2_ASYNC_MATCH_I2C:
> -		return asd_x->match.i2c.adapter_id ==
> -			asd_y->match.i2c.adapter_id &&
> -			asd_x->match.i2c.address ==
> -			asd_y->match.i2c.address;
> +		return match1->i2c.adapter_id == match2->i2c.adapter_id &&
> +			match1->i2c.address == match2->i2c.address;
>  	case V4L2_ASYNC_MATCH_FWNODE:
> -		return asd_x->match.fwnode == asd_y->match.fwnode;
> +		return match1->fwnode == match2->fwnode;
>  	default:
>  		break;
>  	}
> @@ -434,20 +432,20 @@ v4l2_async_nf_unbind_all_subdevs(struct v4l2_async_notifier *notifier,
>  /* See if an async sub-device can be found in a notifier's lists. */
>  static bool
>  __v4l2_async_nf_has_async_subdev(struct v4l2_async_notifier *notifier,
> -				 struct v4l2_async_subdev *asd)
> +				 struct v4l2_async_match *match)

This function should be renamed to drop "subdev" as well.
__v4l2_async_nf_has_match() is a candidate,
__v4l2_async_nf_has_match_entry() is also an option to avoid implying
that the function tests for a match between a subdev and a match entry.

>  {
> -	struct v4l2_async_subdev *asd_y;
> +	struct v4l2_async_subdev *asd;
>  	struct v4l2_subdev *sd;
>  
> -	list_for_each_entry(asd_y, &notifier->waiting, list)
> -		if (asd_equal(asd, asd_y))
> +	list_for_each_entry(asd, &notifier->waiting, list)
> +		if (asd_equal(&asd->match, match))
>  			return true;
>  
>  	list_for_each_entry(sd, &notifier->done, async_list) {
>  		if (WARN_ON(!sd->asd))
>  			continue;
>  
> -		if (asd_equal(asd, sd->asd))
> +		if (asd_equal(&sd->asd->match, match))
>  			return true;
>  	}
>  
> @@ -460,49 +458,50 @@ __v4l2_async_nf_has_async_subdev(struct v4l2_async_notifier *notifier,
>   */
>  static bool
>  v4l2_async_nf_has_async_subdev(struct v4l2_async_notifier *notifier,
> -			       struct v4l2_async_subdev *asd, bool skip_self)
> +			       struct v4l2_async_match *match, bool skip_self)

Same here.

>  {
> -	struct v4l2_async_subdev *asd_y;
> +	struct v4l2_async_subdev *asd;
>  
>  	lockdep_assert_held(&list_lock);
>  
>  	/* Check that an asd is not being added more than once. */
> -	list_for_each_entry(asd_y, &notifier->asd_list, asd_list) {
> -		if (asd == asd_y)
> +	list_for_each_entry(asd, &notifier->asd_list, asd_list) {
> +		if (&asd->match == match)
>  			break;
> -		if (asd_equal(asd, asd_y))
> +		if (asd_equal(&asd->match, match))
>  			return true;
>  	}
>  
>  	/* Check that an asd does not exist in other notifiers. */
>  	list_for_each_entry(notifier, &notifier_list, list)
> -		if (__v4l2_async_nf_has_async_subdev(notifier, asd))
> +		if (__v4l2_async_nf_has_async_subdev(notifier, match))
>  			return true;
>  
>  	return false;
>  }
>  
>  static int v4l2_async_nf_asd_valid(struct v4l2_async_notifier *notifier,
> -				   struct v4l2_async_subdev *asd,
> +				   struct v4l2_async_match *match,
>  				   bool skip_self)

And here.

>  {
>  	struct device *dev =
>  		notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL;
>  
> -	if (!asd)
> +	if (!match)
>  		return -EINVAL;
>  
> -	switch (asd->match.type) {
> +	switch (match->type) {
>  	case V4L2_ASYNC_MATCH_I2C:
>  	case V4L2_ASYNC_MATCH_FWNODE:
> -		if (v4l2_async_nf_has_async_subdev(notifier, asd, skip_self)) {
> +		if (v4l2_async_nf_has_async_subdev(notifier, match,
> +						   skip_self)) {
>  			dev_dbg(dev, "subdev descriptor already listed in this or other notifiers\n");

"match descriptor" ?

>  			return -EEXIST;
>  		}
>  		break;
>  	default:
> -		dev_err(dev, "Invalid match type %u on %p\n",
> -			asd->match.type, asd);
> +		dev_err(dev, "Invalid match type %u on %p\n", match->type,
> +			match);
>  		return -EINVAL;
>  	}
>  
> @@ -526,7 +525,7 @@ static int __v4l2_async_nf_register(struct v4l2_async_notifier *notifier)
>  	mutex_lock(&list_lock);
>  
>  	list_for_each_entry(asd, &notifier->asd_list, asd_list) {
> -		ret = v4l2_async_nf_asd_valid(notifier, asd, true);
> +		ret = v4l2_async_nf_asd_valid(notifier, &asd->match, true);
>  		if (ret)
>  			goto err_unlock;
>  
> @@ -659,7 +658,7 @@ int __v4l2_async_nf_add_subdev(struct v4l2_async_notifier *notifier,
>  
>  	mutex_lock(&list_lock);
>  
> -	ret = v4l2_async_nf_asd_valid(notifier, asd, false);
> +	ret = v4l2_async_nf_asd_valid(notifier, &asd->match, false);
>  	if (ret)
>  		goto unlock;
>  
> @@ -846,15 +845,15 @@ void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
>  EXPORT_SYMBOL(v4l2_async_unregister_subdev);
>  
>  static void print_waiting_subdev(struct seq_file *s,

Same here. v4l2_async_print_match() or v4l2_async_print_match_entry()
could be good names.

In general, it would be useful to have a glossary of terms used in
v4l2-async, and make sure they're used consistently.

> -				 struct v4l2_async_subdev *asd)
> +				 struct v4l2_async_match *match)
>  {
> -	switch (asd->match.type) {
> +	switch (match->type) {
>  	case V4L2_ASYNC_MATCH_I2C:
> -		seq_printf(s, " [i2c] dev=%d-%04x\n", asd->match.i2c.adapter_id,
> -			   asd->match.i2c.address);
> +		seq_printf(s, " [i2c] dev=%d-%04x\n", match->i2c.adapter_id,
> +			   match->i2c.address);
>  		break;
>  	case V4L2_ASYNC_MATCH_FWNODE: {
> -		struct fwnode_handle *devnode, *fwnode = asd->match.fwnode;
> +		struct fwnode_handle *devnode, *fwnode = match->fwnode;
>  
>  		devnode = fwnode_graph_is_endpoint(fwnode) ?
>  			  fwnode_graph_get_port_parent(fwnode) :
> @@ -891,7 +890,7 @@ static int pending_subdevs_show(struct seq_file *s, void *data)
>  	list_for_each_entry(notif, &notifier_list, list) {
>  		seq_printf(s, "%s:\n", v4l2_async_nf_name(notif));
>  		list_for_each_entry(asd, &notif->waiting, list)
> -			print_waiting_subdev(s, asd);
> +			print_waiting_subdev(s, &asd->match);
>  	}
>  
>  	mutex_unlock(&list_lock);

-- 
Regards,

Laurent Pinchart