Commit de9f0c2a authored by Hans Verkuil's avatar Hans Verkuil
Browse files

media: mc: add debugfs node to keep track of requests 



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: default avatarHans Verkuil <hverkuil+cisco@kernel.org>
Signed-off-by: default avatarNicolas Dufresne <nicolas.dufresne@collabora.com>
parent d14d93f9

drivers/media/mc/mc-device.c

+30 −0
Original line number Diff line number Diff line
@@ -679,6 +679,23 @@ void media_device_unregister_entity(struct media_entity *entity) 
}

EXPORT_SYMBOL_GPL(media_device_unregister_entity);



#ifdef CONFIG_DEBUG_FS

/*

 * 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



void media_device_init(struct media_device *mdev)

{

	INIT_LIST_HEAD(&mdev->entities);
@@ -697,6 +714,9 @@ void media_device_init(struct media_device *mdev) 
		media_set_bus_info(mdev->bus_info, sizeof(mdev->bus_info),

				   mdev->dev);



	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);
@@ -748,6 +768,15 @@ int __must_check __media_device_register(struct media_device *mdev, 


	dev_dbg(mdev->dev, "Media device registered\n");



#ifdef CONFIG_DEBUG_FS

	if (!media_debugfs_root)

		media_debugfs_root = debugfs_create_dir("media", NULL);

	mdev->media_dir = debugfs_create_dir(dev_name(&devnode->dev),

					     media_debugfs_root);

	debugfs_create_devm_seqfile(&devnode->dev, "requests",

				    mdev->media_dir, media_device_requests);

#endif



	return 0;

}

EXPORT_SYMBOL_GPL(__media_device_register);
@@ -824,6 +853,7 @@ 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_*() */

drivers/media/mc/mc-devnode.c

+5 −0
Original line number Diff line number Diff line
@@ -45,6 +45,9 @@ 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_debugfs_root;



/* Called when the last user of the media device exits. */

static void media_devnode_release(struct device *cd)

{
@@ -231,6 +234,7 @@ int __must_check media_devnode_register(struct media_device *mdev, 
	if (devnode->parent)

		devnode->dev.parent = devnode->parent;

	dev_set_name(&devnode->dev, "media%d", devnode->minor);

	dev_set_drvdata(&devnode->dev, mdev);

	device_initialize(&devnode->dev);



	/* Part 2: Initialize the character device */
@@ -309,6 +313,7 @@ static int __init media_devnode_init(void) 


static void __exit media_devnode_exit(void)

{

	debugfs_remove_recursive(media_debugfs_root);

	bus_unregister(&media_bus_type);

	unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES);

}

drivers/media/mc/mc-request.c

+6 −0
Original line number Diff line number Diff line
@@ -75,6 +75,7 @@ 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)
@@ -321,6 +322,7 @@ int media_request_alloc(struct media_device *mdev, int *alloc_fd) 


	snprintf(req->debug_str, sizeof(req->debug_str), "%u:%d",

		 atomic_inc_return(&mdev->request_id), *alloc_fd);

	atomic_inc(&mdev->num_requests);

	dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str);



	return 0;
@@ -339,10 +341,12 @@ static void media_request_object_release(struct kref *kref) 
	struct media_request_object *obj =

		container_of(kref, struct media_request_object, kref);

	struct media_request *req = obj->req;

	struct media_device *mdev = obj->mdev;



	if (WARN_ON(req))

		media_request_object_unbind(obj);

	obj->ops->release(obj);

	atomic_dec(&mdev->num_request_objects);

}



struct media_request_object *
@@ -407,6 +411,7 @@ int media_request_object_bind(struct media_request *req, 
	obj->req = req;

	obj->ops = ops;

	obj->priv = priv;

	obj->mdev = req->mdev;



	if (is_buffer)

		list_add_tail(&obj->list, &req->objects);
@@ -414,6 +419,7 @@ int media_request_object_bind(struct media_request *req, 
		list_add(&obj->list, &req->objects);

	req->num_incomplete_objects++;

	ret = 0;

	atomic_inc(&obj->mdev->num_request_objects);



unlock:

	spin_unlock_irqrestore(&req->lock, flags);

include/media/media-device.h

+9 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#ifndef _MEDIA_DEVICE_H

#define _MEDIA_DEVICE_H



#include <linux/atomic.h>

#include <linux/list.h>

#include <linux/mutex.h>

#include <linux/pci.h>
@@ -106,6 +107,9 @@ 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

 * @request_id: Used to generate unique request IDs

 *

 * This structure represents an abstract high-level media device. It allows easy
@@ -179,6 +183,11 @@ 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;

	atomic_t request_id;

};

include/media/media-devnode.h

+4 −0
Original line number Diff line number Diff line
@@ -20,9 +20,13 @@ 
#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_debugfs_root;



/*

 * 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