Re: [PATCH 1/5] media: cec-notifier: Get notifier by device and connector name

[Hans Verkuil]

Hi Neil,

Two small comments below:

On 05/15/18 14:46, Neil Armstrong wrote:
> In non device-tree world, we can need to get the notifier by the driver
> name directly and eventually defer probe if not yet created.
> 
> This patch adds a variant of the get function by using the device name
> instead and will not create a notifier if not yet created.
> 
> But the i915 driver exposes at least 2 HDMI connectors, this patch also
> adds the possibility to add a connector name tied to the notifier device
> to form a tuple and associate different CEC controllers for each HDMI
> connectors.
> 
> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> ---
>  drivers/media/cec/cec-notifier.c | 12 +++++++++---
>  include/media/cec-notifier.h     | 30 ++++++++++++++++++++++++++++--
>  2 files changed, 37 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/media/cec/cec-notifier.c b/drivers/media/cec/cec-notifier.c
> index 16dffa0..7038abae1 100644
> --- a/drivers/media/cec/cec-notifier.c
> +++ b/drivers/media/cec/cec-notifier.c
> @@ -21,6 +21,7 @@ struct cec_notifier {
>  	struct list_head head;
>  	struct kref kref;
>  	struct device *dev;
> +	const char *conn;
>  	struct cec_adapter *cec_adap;
>  	void (*callback)(struct cec_adapter *adap, u16 pa);
>  
> @@ -30,13 +31,14 @@ struct cec_notifier {
>  static LIST_HEAD(cec_notifiers);
>  static DEFINE_MUTEX(cec_notifiers_lock);
>  
> -struct cec_notifier *cec_notifier_get(struct device *dev)
> +struct cec_notifier *cec_notifier_get_conn(struct device *dev, const char *conn)
>  {
>  	struct cec_notifier *n;
>  
>  	mutex_lock(&cec_notifiers_lock);
>  	list_for_each_entry(n, &cec_notifiers, head) {
> -		if (n->dev == dev) {
> +		if (n->dev == dev &&
> +		    (!conn || !strcmp(n->conn, conn))) {
>  			kref_get(&n->kref);
>  			mutex_unlock(&cec_notifiers_lock);
>  			return n;
> @@ -46,6 +48,8 @@ struct cec_notifier *cec_notifier_get(struct device *dev)
>  	if (!n)
>  		goto unlock;
>  	n->dev = dev;
> +	if (conn)
> +		n->conn = kstrdup(conn, GFP_KERNEL);
>  	n->phys_addr = CEC_PHYS_ADDR_INVALID;
>  	mutex_init(&n->lock);
>  	kref_init(&n->kref);
> @@ -54,7 +58,7 @@ struct cec_notifier *cec_notifier_get(struct device *dev)
>  	mutex_unlock(&cec_notifiers_lock);
>  	return n;
>  }
> -EXPORT_SYMBOL_GPL(cec_notifier_get);
> +EXPORT_SYMBOL_GPL(cec_notifier_get_conn);
>  
>  static void cec_notifier_release(struct kref *kref)
>  {
> @@ -62,6 +66,8 @@ static void cec_notifier_release(struct kref *kref)
>  		container_of(kref, struct cec_notifier, kref);
>  
>  	list_del(&n->head);
> +	if (n->conn)

No need for this if, kfree already tests the pointer.

> +		kfree(n->conn);
>  	kfree(n);
>  }
>  
> diff --git a/include/media/cec-notifier.h b/include/media/cec-notifier.h
> index cf0add7..73f92c7 100644
> --- a/include/media/cec-notifier.h
> +++ b/include/media/cec-notifier.h
> @@ -20,6 +20,23 @@ struct cec_notifier;
>  #if IS_REACHABLE(CONFIG_CEC_CORE) && IS_ENABLED(CONFIG_CEC_NOTIFIER)
>  
>  /**
> + * cec_notifier_get_conn - find or create a new cec_notifier for the given
> + * device and connector tuple.
> + * @dev: device that sends the events.
> + * @conn: the connector name from which the event occurs
> + *
> + * If a notifier for device @dev already exists, then increase the refcount
> + * and return that notifier.
> + *
> + * If it doesn't exist, then allocate a new notifier struct and return a
> + * pointer to that new struct.
> + *
> + * Return NULL if the memory could not be allocated.
> + */
> +struct cec_notifier *cec_notifier_get_conn(struct device *dev,
> +					   const char *conn);
> +
> +/**
>   * cec_notifier_get - find or create a new cec_notifier for the given device.
>   * @dev: device that sends the events.
>   *
> @@ -31,7 +48,10 @@ struct cec_notifier;
>   *
>   * Return NULL if the memory could not be allocated.
>   */
> -struct cec_notifier *cec_notifier_get(struct device *dev);
> +static inline struct cec_notifier *cec_notifier_get(struct device *dev)
> +{
> +	return cec_notifier_get_conn(dev, NULL);
> +}
>  
>  /**
>   * cec_notifier_put - decrease refcount and delete when the refcount reaches 0.
> @@ -85,12 +105,18 @@ void cec_register_cec_notifier(struct cec_adapter *adap,
>  			       struct cec_notifier *notifier);
>  
>  #else
> -static inline struct cec_notifier *cec_notifier_get(struct device *dev)
> +static inline struct cec_notifier *cec_notifier_get_conn(struct device *dev,
> +							 const char *conn)
>  {
>  	/* A non-NULL pointer is expected on success */
>  	return (struct cec_notifier *)0xdeadfeed;
>  }
>  
> +static inline struct cec_notifier *cec_notifier_get(struct device *dev)
> +{
> +	return cec_notifier_get_conn(dev, NULL);
> +}

Just move this function to after the #if ... #else ... #endif
After all, it is the same static inline for both.

> +
>  static inline void cec_notifier_put(struct cec_notifier *n)
>  {
>  }
> 

Regards,

	Hans