Re: [PATCHv17 34/34] RFC: media-requests: add debugfs node

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Em Sat,  4 Aug 2018 14:45:26 +0200
Hans Verkuil <hverkuil@xxxxxxxxx> escreveu:

> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> 
> Keep track of the number of requests and request objects of a media
> device. Helps to verify that all request-related memory is freed.
> 
> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>



> ---
>  drivers/media/media-device.c  | 41 +++++++++++++++++++++++++++++++++++
>  drivers/media/media-devnode.c | 17 +++++++++++++++
>  drivers/media/media-request.c |  5 +++++
>  include/media/media-device.h  | 11 ++++++++++
>  include/media/media-devnode.h |  4 ++++
>  include/media/media-request.h |  2 ++
>  6 files changed, 80 insertions(+)
> 
> diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
> index 4b9a8de05562..28a891b53886 100644
> --- a/drivers/media/media-device.c
> +++ b/drivers/media/media-device.c
> @@ -691,6 +691,23 @@ void media_device_unregister_entity(struct media_entity *entity)
>  }
>  EXPORT_SYMBOL_GPL(media_device_unregister_entity);
>  
> +#ifdef CONFIG_DEBUG_FS

Patch itself looks good. Yet, perhaps we could request both
CONFIG_DEBUG_FS and CONFIG_VIDEO_ADV_DEBUG.

Also, instead of ifdef, please use IS_ENABLED for DEBUG_FS. That tends
to be safer long term.

With that:

Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>

> +/*
> + * Log the state of media requests.
> + * Very useful for debugging.
> + */
> +static int media_device_requests(struct seq_file *file, void *priv)
> +{
> +	struct media_device *dev = dev_get_drvdata(file->private);
> +
> +	seq_printf(file, "number of requests: %d\n",
> +		   atomic_read(&dev->num_requests));
> +	seq_printf(file, "number of request objects: %d\n",
> +		   atomic_read(&dev->num_request_objects));
> +	return 0;
> +}
> +#endif
> +
>  /**
>   * media_device_init() - initialize a media device
>   * @mdev:	The media device
> @@ -713,6 +730,9 @@ void media_device_init(struct media_device *mdev)
>  	mutex_init(&mdev->graph_mutex);
>  	ida_init(&mdev->entity_internal_idx);
>  
> +	atomic_set(&mdev->num_requests, 0);
> +	atomic_set(&mdev->num_request_objects, 0);
> +
>  	dev_dbg(mdev->dev, "Media device initialized\n");
>  }
>  EXPORT_SYMBOL_GPL(media_device_init);
> @@ -764,6 +784,26 @@ int __must_check __media_device_register(struct media_device *mdev,
>  
>  	dev_dbg(mdev->dev, "Media device registered\n");
>  
> +#ifdef CONFIG_DEBUG_FS
> +	if (!media_top_dir)
> +		return 0;
> +
> +	mdev->media_dir = debugfs_create_dir(dev_name(&devnode->dev),
> +					     media_top_dir);
> +	if (IS_ERR_OR_NULL(mdev->media_dir)) {
> +		dev_warn(mdev->dev, "Failed to create debugfs dir\n");
> +		return 0;
> +	}
> +	mdev->requests_file = debugfs_create_devm_seqfile(&devnode->dev,
> +		"requests", mdev->media_dir, media_device_requests);
> +	if (IS_ERR_OR_NULL(mdev->requests_file)) {
> +		dev_warn(mdev->dev, "Failed to create requests file\n");
> +		debugfs_remove_recursive(mdev->media_dir);
> +		mdev->media_dir = NULL;
> +		return 0;
> +	}
> +#endif
> +
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(__media_device_register);
> @@ -841,6 +881,7 @@ void media_device_unregister(struct media_device *mdev)
>  
>  	dev_dbg(mdev->dev, "Media device unregistered\n");
>  
> +	debugfs_remove_recursive(mdev->media_dir);
>  	device_remove_file(&mdev->devnode->dev, &dev_attr_model);
>  	media_devnode_unregister(mdev->devnode);
>  	/* devnode free is handled in media_devnode_*() */
> diff --git a/drivers/media/media-devnode.c b/drivers/media/media-devnode.c
> index 6b87a721dc49..4358ed22f208 100644
> --- a/drivers/media/media-devnode.c
> +++ b/drivers/media/media-devnode.c
> @@ -53,6 +53,12 @@ static dev_t media_dev_t;
>  static DEFINE_MUTEX(media_devnode_lock);
>  static DECLARE_BITMAP(media_devnode_nums, MEDIA_NUM_DEVICES);
>  
> +/*
> + * debugfs
> + */
> +struct dentry *media_top_dir;
> +
> +
>  /* Called when the last user of the media device exits. */
>  static void media_devnode_release(struct device *cd)
>  {
> @@ -259,6 +265,8 @@ int __must_check media_devnode_register(struct media_device *mdev,
>  		goto cdev_add_error;
>  	}
>  
> +	dev_set_drvdata(&devnode->dev, mdev);
> +
>  	/* Part 4: Activate this minor. The char device can now be used. */
>  	set_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
>  
> @@ -310,6 +318,14 @@ static int __init media_devnode_init(void)
>  		return ret;
>  	}
>  
> +#ifdef CONFIG_DEBUG_FS
> +	media_top_dir = debugfs_create_dir("media", NULL);
> +	if (IS_ERR_OR_NULL(media_top_dir)) {
> +		pr_warn("Failed to create debugfs media dir\n");
> +		media_top_dir = NULL;
> +	}
> +#endif
> +
>  	ret = bus_register(&media_bus_type);
>  	if (ret < 0) {
>  		unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES);
> @@ -322,6 +338,7 @@ static int __init media_devnode_init(void)
>  
>  static void __exit media_devnode_exit(void)
>  {
> +	debugfs_remove_recursive(media_top_dir);
>  	bus_unregister(&media_bus_type);
>  	unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES);
>  }
> diff --git a/drivers/media/media-request.c b/drivers/media/media-request.c
> index a5b70a4e613b..8ba97a9c4bf1 100644
> --- a/drivers/media/media-request.c
> +++ b/drivers/media/media-request.c
> @@ -72,6 +72,7 @@ static void media_request_release(struct kref *kref)
>  		mdev->ops->req_free(req);
>  	else
>  		kfree(req);
> +	atomic_dec(&mdev->num_requests);
>  }
>  
>  void media_request_put(struct media_request *req)
> @@ -318,6 +319,7 @@ int media_request_alloc(struct media_device *mdev,
>  	get_task_comm(comm, current);
>  	snprintf(req->debug_str, sizeof(req->debug_str), "%s:%d",
>  		 comm, fd);
> +	atomic_inc(&mdev->num_requests);
>  	dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str);
>  
>  	fd_install(fd, filp);
> @@ -342,6 +344,7 @@ static void media_request_object_release(struct kref *kref)
>  	if (WARN_ON(req))
>  		media_request_object_unbind(obj);
>  	obj->ops->release(obj);
> +	atomic_dec(&obj->mdev->num_request_objects);
>  }
>  
>  struct media_request_object *
> @@ -405,10 +408,12 @@ int media_request_object_bind(struct media_request *req,
>  	obj->req = req;
>  	obj->ops = ops;
>  	obj->priv = priv;
> +	obj->mdev = req->mdev;
>  
>  	list_add_tail(&obj->list, &req->objects);
>  	req->num_incomplete_objects++;
>  	ret = 0;
> +	atomic_inc(&obj->mdev->num_request_objects);
>  
>  unlock:
>  	spin_unlock_irqrestore(&req->lock, flags);
> diff --git a/include/media/media-device.h b/include/media/media-device.h
> index 110b89567671..2de0606938d4 100644
> --- a/include/media/media-device.h
> +++ b/include/media/media-device.h
> @@ -21,6 +21,7 @@
>  
>  #include <linux/list.h>
>  #include <linux/mutex.h>
> +#include <linux/atomic.h>
>  
>  #include <media/media-devnode.h>
>  #include <media/media-entity.h>
> @@ -107,6 +108,10 @@ struct media_device_ops {
>   * @ops:	Operation handler callbacks
>   * @req_queue_mutex: Serialise the MEDIA_REQUEST_IOC_QUEUE ioctl w.r.t.
>   *		     other operations that stop or start streaming.
> + * @num_requests: number of associated requests
> + * @num_request_objects: number of associated request objects
> + * @media_dir:	DebugFS media directory
> + * @requests_file: DebugFS requests file
>   *
>   * This structure represents an abstract high-level media device. It allows easy
>   * access to entities and provides basic media device-level support. The
> @@ -179,6 +184,12 @@ struct media_device {
>  	const struct media_device_ops *ops;
>  
>  	struct mutex req_queue_mutex;
> +	atomic_t num_requests;
> +	atomic_t num_request_objects;
> +
> +	/* debugfs */
> +	struct dentry *media_dir;
> +	struct dentry *requests_file;
>  };
>  
>  /* We don't need to include pci.h or usb.h here */
> diff --git a/include/media/media-devnode.h b/include/media/media-devnode.h
> index dc2f64e1b08f..984b62b634d3 100644
> --- a/include/media/media-devnode.h
> +++ b/include/media/media-devnode.h
> @@ -28,9 +28,13 @@
>  #include <linux/fs.h>
>  #include <linux/device.h>
>  #include <linux/cdev.h>
> +#include <linux/debugfs.h>
>  
>  struct media_device;
>  
> +/* DebugFS top-level media directory */
> +extern struct dentry *media_top_dir;
> +
>  /*
>   * Flag to mark the media_devnode struct as registered. Drivers must not touch
>   * this flag directly, it will be set and cleared by media_devnode_register and
> diff --git a/include/media/media-request.h b/include/media/media-request.h
> index fd08d7a431a1..76727d4a89c3 100644
> --- a/include/media/media-request.h
> +++ b/include/media/media-request.h
> @@ -210,6 +210,7 @@ struct media_request_object_ops {
>   * struct media_request_object - An opaque object that belongs to a media
>   *				 request
>   *
> + * @mdev: Media device this object belongs to
>   * @ops: object's operations
>   * @priv: object's priv pointer
>   * @req: the request this object belongs to (can be NULL)
> @@ -221,6 +222,7 @@ struct media_request_object_ops {
>   * another struct that contains the actual data for this request object.
>   */
>  struct media_request_object {
> +	struct media_device *mdev;
>  	const struct media_request_object_ops *ops;
>  	void *priv;
>  	struct media_request *req;



Thanks,
Mauro



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